diff --git a/CMakeLists.txt b/CMakeLists.txt
index 08b48d2eb..6401ab105 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -751,6 +751,8 @@ set(SOURCES
         utilities/debug.cc
         utilities/env_mirror.cc
         utilities/env_timed.cc
+        utilities/fault_injection_env.cc
+        utilities/fault_injection_fs.cc
         utilities/leveldb_options/leveldb_options.cc
         utilities/memory/memory_util.cc
         utilities/merge_operators/bytesxor.cc
@@ -1172,8 +1174,6 @@ if(WITH_TESTS)
       db/db_test_util.cc
       monitoring/thread_status_updater_debug.cc
       table/mock_table.cc
-      test_util/fault_injection_test_env.cc
-      test_util/fault_injection_test_fs.cc
       utilities/cassandra/test_utils.cc
   )
   enable_testing()
diff --git a/Makefile b/Makefile
index ccbf8e054..9a5da537b 100644
--- a/Makefile
+++ b/Makefile
@@ -636,18 +636,12 @@ LIBRARY=$(SHARED1)
 TEST_LIBRARY=$(SHARED_TEST_LIBRARY)
 TOOLS_LIBRARY=$(SHARED_TOOLS_LIBRARY)
 STRESS_LIBRARY=$(SHARED_STRESS_LIBRARY)
-ifeq ($(DEBUG_LEVEL),0)
-STRESS_LIBRARY_RUNTIME_DEPS=$(SHARED_TOOLS_LIBRARY)
-else
-STRESS_LIBRARY_RUNTIME_DEPS=$(SHARED_TEST_LIBRARY) $(SHARED_TOOLS_LIBRARY)
-endif
 CLOUD_LIBRARY=$(SHARED_CLOUD_LIBRARY)
 else
 LIBRARY=$(STATIC_LIBRARY)
 TEST_LIBRARY=$(STATIC_TEST_LIBRARY)
 TOOLS_LIBRARY=$(STATIC_TOOLS_LIBRARY)
 STRESS_LIBRARY=$(STATIC_STRESS_LIBRARY)
-STRESS_LIBRARY_RUNTIME_DEPS=
 endif
 
 ROCKSDB_MAJOR = $(shell egrep "ROCKSDB_MAJOR.[0-9]" include/rocksdb/version.h | cut -d ' ' -f 3)
@@ -1166,29 +1160,23 @@ $(STATIC_TEST_LIBRARY): $(TEST_OBJECTS)
 	$(AM_V_AR)rm -f $@ $(SHARED_TEST_LIBRARY)
 	$(AM_V_at)$(AR) $(ARFLAGS) $@ $^
 
-$(STATIC_TOOLS_LIBRARY): $(BENCH_OBJECTS) $(TOOL_OBJECTS) $(TESTUTIL)
+$(STATIC_TOOLS_LIBRARY): $(BENCH_OBJECTS) $(TOOL_OBJECTS)
 	$(AM_V_AR)rm -f $@ $(SHARED_TOOLS_LIBRARY)
 	$(AM_V_at)$(AR) $(ARFLAGS) $@ $^
 
-ifeq ($(DEBUG_LEVEL),0)
-$(STATIC_STRESS_LIBRARY): $(TESTUTIL) $(ANALYZE_OBJECTS) $(STRESS_OBJECTS)
+$(STATIC_STRESS_LIBRARY): $(ANALYZE_OBJECTS) $(STRESS_OBJECTS)
 	$(AM_V_AR)rm -f $@ $(SHARED_STRESS_LIBRARY)
 	$(AM_V_at)$(AR) $(ARFLAGS) $@ $^
-else
-$(STATIC_STRESS_LIBRARY): $(TEST_OBJECTS) $(ANALYZE_OBJECTS) $(STRESS_OBJECTS)
-	$(AM_V_AR)rm -f $@ $(SHARED_STRESS_LIBRARY)
-	$(AM_V_at)$(AR) $(ARFLAGS) $@ $^
-endif
 
 $(SHARED_TEST_LIBRARY): $(TEST_OBJECTS) $(SHARED1)
 	$(AM_V_AR)rm -f $@ $(STATIC_TEST_LIBRARY)
 	$(AM_SHARE)
 
-$(SHARED_TOOLS_LIBRARY): $(TOOL_OBJECTS) $(TESTUTIL) $(SHARED1)
+$(SHARED_TOOLS_LIBRARY): $(TOOL_OBJECTS) $(SHARED1)
 	$(AM_V_AR)rm -f $@ $(STATIC_TOOLS_LIBRARY)
 	$(AM_SHARE)
 
-$(SHARED_STRESS_LIBRARY): $(ANALYZE_OBJECTS) $(STRESS_OBJECTS) $(STRESS_LIBRARY_RUNTIME_DEPS) $(SHARED1)
+$(SHARED_STRESS_LIBRARY): $(ANALYZE_OBJECTS) $(STRESS_OBJECTS) $(SHARED_TOOLS_LIBRARY) $(SHARED1)
 	$(AM_V_AR)rm -f $@ $(STATIC_STRESS_LIBRARY)
 	$(AM_SHARE)
 
@@ -1216,13 +1204,13 @@ cache_bench: $(OBJ_DIR)/cache/cache_bench.o $(LIBRARY)
 persistent_cache_bench: $(OBJ_DIR)/utilities/persistent_cache/persistent_cache_bench.o $(LIBRARY)
 	$(AM_LINK)
 
-memtablerep_bench: $(OBJ_DIR)/memtable/memtablerep_bench.o $(TESTUTIL) $(LIBRARY)
+memtablerep_bench: $(OBJ_DIR)/memtable/memtablerep_bench.o $(LIBRARY)
 	$(AM_LINK)
 
 filter_bench: $(OBJ_DIR)/util/filter_bench.o $(LIBRARY)
 	$(AM_LINK)
 
-db_stress: $(OBJ_DIR)/db_stress_tool/db_stress.o $(STRESS_LIBRARY) $(STRESS_LIBRARY_RUNTIME_DEPS) $(LIBRARY)
+db_stress: $(OBJ_DIR)/db_stress_tool/db_stress.o $(STRESS_LIBRARY) $(TOOLS_LIBRARY) $(LIBRARY)
 	$(AM_LINK)
 
 write_stress: $(OBJ_DIR)/tools/write_stress.o $(LIBRARY)
@@ -1231,7 +1219,7 @@ write_stress: $(OBJ_DIR)/tools/write_stress.o $(LIBRARY)
 db_sanity_test: $(OBJ_DIR)/tools/db_sanity_test.o $(LIBRARY)
 	$(AM_LINK)
 
-db_repl_stress: $(OBJ_DIR)/tools/db_repl_stress.o $(TESTUTIL) $(LIBRARY)
+db_repl_stress: $(OBJ_DIR)/tools/db_repl_stress.o $(LIBRARY)
 	$(AM_LINK)
 
 arena_test: $(OBJ_DIR)/memory/arena_test.o $(TEST_LIBRARY) $(LIBRARY)
diff --git a/TARGETS b/TARGETS
index becaff39f..c888ce5b0 100644
--- a/TARGETS
+++ b/TARGETS
@@ -332,6 +332,8 @@ cpp_library(
         "utilities/debug.cc",
         "utilities/env_mirror.cc",
         "utilities/env_timed.cc",
+        "utilities/fault_injection_env.cc",
+        "utilities/fault_injection_fs.cc",
         "utilities/leveldb_options/leveldb_options.cc",
         "utilities/memory/memory_util.cc",
         "utilities/merge_operators/bytesxor.cc",
@@ -385,8 +387,6 @@ cpp_library(
     srcs = [
         "db/db_test_util.cc",
         "table/mock_table.cc",
-        "test_util/fault_injection_test_env.cc",
-        "test_util/fault_injection_test_fs.cc",
         "test_util/testharness.cc",
         "test_util/testutil.cc",
         "tools/block_cache_analyzer/block_cache_trace_analyzer.cc",
diff --git a/db/column_family_test.cc b/db/column_family_test.cc
index c4181d9b8..04ef9a30f 100644
--- a/db/column_family_test.cc
+++ b/db/column_family_test.cc
@@ -22,26 +22,18 @@
 #include "rocksdb/env.h"
 #include "rocksdb/iterator.h"
 #include "rocksdb/utilities/object_registry.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/sync_point.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
 #include "util/coding.h"
 #include "util/string_util.h"
+#include "utilities/fault_injection_env.h"
 #include "utilities/merge_operators.h"
 
 namespace ROCKSDB_NAMESPACE {
 
 static const int kValueSize = 1000;
 
-namespace {
-std::string RandomString(Random* rnd, int len) {
-  std::string r;
-  test::RandomString(rnd, len, &r);
-  return r;
-}
-}  // anonymous namespace
-
 // counts how many operations were performed
 class EnvCounter : public EnvWrapper {
  public:
@@ -109,11 +101,11 @@ class ColumnFamilyTestBase : public testing::Test {
       // preserves the implementation that was in place when all of the
       // magic values in this file were picked.
       *storage = std::string(kValueSize, ' ');
-      return Slice(*storage);
     } else {
       Random r(k);
-      return test::RandomString(&r, kValueSize, storage);
+      *storage = r.RandomString(kValueSize);
     }
+    return Slice(*storage);
   }
 
   void Build(int base, int n, int flush_every = 0) {
@@ -329,11 +321,11 @@ class ColumnFamilyTestBase : public testing::Test {
       // 10 bytes for key, rest is value
       if (!save) {
         ASSERT_OK(Put(cf, test::RandomKey(&rnd_, 11),
-                      RandomString(&rnd_, key_value_size - 10)));
+                      rnd_.RandomString(key_value_size - 10)));
       } else {
         std::string key = test::RandomKey(&rnd_, 11);
         keys_[cf].insert(key);
-        ASSERT_OK(Put(cf, key, RandomString(&rnd_, key_value_size - 10)));
+        ASSERT_OK(Put(cf, key, rnd_.RandomString(key_value_size - 10)));
       }
     }
     db_->FlushWAL(false);
diff --git a/db/comparator_db_test.cc b/db/comparator_db_test.cc
index 49f287a97..4eac91e2a 100644
--- a/db/comparator_db_test.cc
+++ b/db/comparator_db_test.cc
@@ -13,6 +13,7 @@
 #include "test_util/testutil.h"
 #include "util/hash.h"
 #include "util/kv_map.h"
+#include "util/random.h"
 #include "util/string_util.h"
 #include "utilities/merge_operators.h"
 
@@ -342,12 +343,12 @@ TEST_P(ComparatorDBTest, SimpleSuffixReverseComparator) {
     std::vector<std::string> source_prefixes;
     // Randomly generate 5 prefixes
     for (int i = 0; i < 5; i++) {
-      source_prefixes.push_back(test::RandomHumanReadableString(&rnd, 8));
+      source_prefixes.push_back(rnd.HumanReadableString(8));
     }
     for (int j = 0; j < 20; j++) {
       int prefix_index = rnd.Uniform(static_cast<int>(source_prefixes.size()));
       std::string key = source_prefixes[prefix_index] +
-                        test::RandomHumanReadableString(&rnd, rnd.Uniform(8));
+                        rnd.HumanReadableString(rnd.Uniform(8));
       source_strings.push_back(key);
     }
 
diff --git a/db/corruption_test.cc b/db/corruption_test.cc
index 4641ec7b1..cae3ad728 100644
--- a/db/corruption_test.cc
+++ b/db/corruption_test.cc
@@ -9,13 +9,13 @@
 
 #ifndef ROCKSDB_LITE
 
-#include "rocksdb/db.h"
-
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+
 #include <cinttypes>
+
 #include "db/db_impl/db_impl.h"
 #include "db/db_test_util.h"
 #include "db/log_format.h"
@@ -24,6 +24,7 @@
 #include "file/filename.h"
 #include "rocksdb/cache.h"
 #include "rocksdb/convenience.h"
+#include "rocksdb/db.h"
 #include "rocksdb/env.h"
 #include "rocksdb/table.h"
 #include "rocksdb/write_batch.h"
@@ -31,6 +32,7 @@
 #include "table/meta_blocks.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
+#include "util/random.h"
 #include "util/string_util.h"
 
 namespace ROCKSDB_NAMESPACE {
@@ -219,11 +221,11 @@ class CorruptionTest : public testing::Test {
       // preserves the implementation that was in place when all of the
       // magic values in this file were picked.
       *storage = std::string(kValueSize, ' ');
-      return Slice(*storage);
     } else {
       Random r(k);
-      return test::RandomString(&r, kValueSize, storage);
+      *storage = r.RandomString(kValueSize);
     }
+    return Slice(*storage);
   }
 };
 
diff --git a/db/db_basic_test.cc b/db/db_basic_test.cc
index 3cf52f71b..3795a08b7 100644
--- a/db/db_basic_test.cc
+++ b/db/db_basic_test.cc
@@ -16,10 +16,11 @@
 #include "rocksdb/utilities/debug.h"
 #include "table/block_based/block_based_table_reader.h"
 #include "table/block_based/block_builder.h"
-#include "test_util/fault_injection_test_env.h"
 #if !defined(ROCKSDB_LITE)
 #include "test_util/sync_point.h"
 #endif
+#include "util/random.h"
+#include "utilities/fault_injection_env.h"
 #include "utilities/merge_operators.h"
 #include "utilities/merge_operators/string_append/stringappend.h"
 
@@ -2040,7 +2041,7 @@ TEST_F(DBBasicTest, MultiGetIOBufferOverrun) {
   for (int i = 0; i < 100; ++i) {
     // Make the value compressible. A purely random string doesn't compress
     // and the resultant data block will not be compressed
-    std::string value(RandomString(&rnd, 128) + zero_str);
+    std::string value(rnd.RandomString(128) + zero_str);
     assert(Put(Key(i), value) == Status::OK());
   }
   Flush();
@@ -2430,7 +2431,7 @@ class DBBasicTestMultiGet : public DBTestBase {
       for (int i = 0; i < 100; ++i) {
         // Make the value compressible. A purely random string doesn't compress
         // and the resultant data block will not be compressed
-        values_.emplace_back(RandomString(&rnd, 128) + zero_str);
+        values_.emplace_back(rnd.RandomString(128) + zero_str);
         assert(((num_cfs == 1) ? Put(Key(i), values_[i])
                                : Put(cf, Key(i), values_[i])) == Status::OK());
       }
@@ -2442,7 +2443,7 @@ class DBBasicTestMultiGet : public DBTestBase {
 
       for (int i = 0; i < 100; ++i) {
         // block cannot gain space by compression
-        uncompressable_values_.emplace_back(RandomString(&rnd, 256) + '\0');
+        uncompressable_values_.emplace_back(rnd.RandomString(256) + '\0');
         std::string tmp_key = "a" + Key(i);
         assert(((num_cfs == 1) ? Put(tmp_key, uncompressable_values_[i])
                                : Put(cf, tmp_key, uncompressable_values_[i])) ==
@@ -3210,7 +3211,7 @@ TEST_F(DBBasicTest, PointLookupDeadline) {
     Random rnd(301);
     for (int i = 0; i < 400; ++i) {
       std::string key = "k" + ToString(i);
-      Put(key, RandomString(&rnd, 100));
+      Put(key, rnd.RandomString(100));
     }
     Flush();
 
diff --git a/db/db_block_cache_test.cc b/db/db_block_cache_test.cc
index 0841a655e..045967de3 100644
--- a/db/db_block_cache_test.cc
+++ b/db/db_block_cache_test.cc
@@ -7,10 +7,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 #include <cstdlib>
+
 #include "cache/lru_cache.h"
 #include "db/db_test_util.h"
 #include "port/stack_trace.h"
 #include "util/compression.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -764,7 +766,7 @@ TEST_F(DBBlockCacheTest, CompressedCache) {
     std::string str;
     for (int i = 0; i < num_iter; i++) {
       if (i % 4 == 0) {  // high compression ratio
-        str = RandomString(&rnd, 1000);
+        str = rnd.RandomString(1000);
       }
       values.push_back(str);
       ASSERT_OK(Put(1, Key(i), values[i]));
@@ -851,7 +853,7 @@ TEST_F(DBBlockCacheTest, CacheCompressionDict) {
     for (int i = 0; i < kNumFiles; ++i) {
       ASSERT_EQ(i, NumTableFilesAtLevel(0, 0));
       for (int j = 0; j < kNumEntriesPerFile; ++j) {
-        std::string value = RandomString(&rnd, kNumBytesPerEntry);
+        std::string value = rnd.RandomString(kNumBytesPerEntry);
         ASSERT_OK(Put(Key(j * kNumFiles + i), value.c_str()));
       }
       ASSERT_OK(Flush());
diff --git a/db/db_compaction_test.cc b/db/db_compaction_test.cc
index eb86ec2dc..aae1c1100 100644
--- a/db/db_compaction_test.cc
+++ b/db/db_compaction_test.cc
@@ -14,9 +14,10 @@
 #include "rocksdb/experimental.h"
 #include "rocksdb/sst_file_writer.h"
 #include "rocksdb/utilities/convenience.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/sync_point.h"
 #include "util/concurrent_task_limiter_impl.h"
+#include "util/random.h"
+#include "utilities/fault_injection_env.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -295,7 +296,7 @@ TEST_P(DBCompactionTestWithParam, CompactionDeletionTrigger) {
     const int kTestSize = kCDTKeysPerBuffer * 1024;
     std::vector<std::string> values;
     for (int k = 0; k < kTestSize; ++k) {
-      values.push_back(RandomString(&rnd, kCDTValueSize));
+      values.push_back(rnd.RandomString(kCDTValueSize));
       ASSERT_OK(Put(Key(k), values[k]));
     }
     dbfull()->TEST_WaitForFlushMemTable();
@@ -343,7 +344,7 @@ TEST_P(DBCompactionTestWithParam, CompactionsPreserveDeletes) {
     const int kTestSize = kCDTKeysPerBuffer;
     std::vector<std::string> values;
     for (int k = 0; k < kTestSize; ++k) {
-      values.push_back(RandomString(&rnd, kCDTValueSize));
+      values.push_back(rnd.RandomString(kCDTValueSize));
       ASSERT_OK(Put(Key(k), values[k]));
     }
 
@@ -408,7 +409,7 @@ TEST_F(DBCompactionTest, SkipStatsUpdateTest) {
   const int kTestSize = kCDTKeysPerBuffer * 512;
   std::vector<std::string> values;
   for (int k = 0; k < kTestSize; ++k) {
-    values.push_back(RandomString(&rnd, kCDTValueSize));
+    values.push_back(rnd.RandomString(kCDTValueSize));
     ASSERT_OK(Put(Key(k), values[k]));
   }
 
@@ -555,7 +556,7 @@ TEST_P(DBCompactionTestWithParam, CompactionDeletionTriggerReopen) {
     const int kTestSize = kCDTKeysPerBuffer * 512;
     std::vector<std::string> values;
     for (int k = 0; k < kTestSize; ++k) {
-      values.push_back(RandomString(&rnd, kCDTValueSize));
+      values.push_back(rnd.RandomString(kCDTValueSize));
       ASSERT_OK(Put(Key(k), values[k]));
     }
     dbfull()->TEST_WaitForFlushMemTable();
@@ -673,7 +674,7 @@ TEST_F(DBCompactionTest, DisableStatsUpdateReopen) {
     const int kTestSize = kCDTKeysPerBuffer * 512;
     std::vector<std::string> values;
     for (int k = 0; k < kTestSize; ++k) {
-      values.push_back(RandomString(&rnd, kCDTValueSize));
+      values.push_back(rnd.RandomString(kCDTValueSize));
       ASSERT_OK(Put(Key(k), values[k]));
     }
     dbfull()->TEST_WaitForFlushMemTable();
@@ -736,7 +737,7 @@ TEST_P(DBCompactionTestWithParam, CompactionTrigger) {
     std::vector<std::string> values;
     // Write 100KB (100 values, each 1K)
     for (int i = 0; i < kNumKeysPerFile; i++) {
-      values.push_back(RandomString(&rnd, 990));
+      values.push_back(rnd.RandomString(990));
       ASSERT_OK(Put(1, Key(i), values[i]));
     }
     // put extra key to trigger flush
@@ -748,7 +749,7 @@ TEST_P(DBCompactionTestWithParam, CompactionTrigger) {
   // generate one more file in level-0, and should trigger level-0 compaction
   std::vector<std::string> values;
   for (int i = 0; i < kNumKeysPerFile; i++) {
-    values.push_back(RandomString(&rnd, 990));
+    values.push_back(rnd.RandomString(990));
     ASSERT_OK(Put(1, Key(i), values[i]));
   }
   // put extra key to trigger flush
@@ -867,7 +868,7 @@ TEST_P(DBCompactionTestWithParam, CompactionsGenerateMultipleFiles) {
   ASSERT_EQ(NumTableFilesAtLevel(0, 1), 0);
   std::vector<std::string> values;
   for (int i = 0; i < 80; i++) {
-    values.push_back(RandomString(&rnd, 100000));
+    values.push_back(rnd.RandomString(100000));
     ASSERT_OK(Put(1, Key(i), values[i]));
   }
 
@@ -1105,7 +1106,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveOneFile) {
   Random rnd(301);
   std::vector<std::string> values;
   for (int i = 0; i < num_keys; i++) {
-    values.push_back(RandomString(&rnd, value_size));
+    values.push_back(rnd.RandomString(value_size));
     ASSERT_OK(Put(Key(i), values[i]));
   }
 
@@ -1177,7 +1178,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveNonOverlappingFiles) {
   std::map<int32_t, std::string> values;
   for (size_t i = 0; i < ranges.size(); i++) {
     for (int32_t j = ranges[i].first; j <= ranges[i].second; j++) {
-      values[j] = RandomString(&rnd, value_size);
+      values[j] = rnd.RandomString(value_size);
       ASSERT_OK(Put(Key(j), values[j]));
     }
     ASSERT_OK(Flush());
@@ -1223,7 +1224,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveNonOverlappingFiles) {
   };
   for (size_t i = 0; i < ranges.size(); i++) {
     for (int32_t j = ranges[i].first; j <= ranges[i].second; j++) {
-      values[j] = RandomString(&rnd, value_size);
+      values[j] = rnd.RandomString(value_size);
       ASSERT_OK(Put(Key(j), values[j]));
     }
     ASSERT_OK(Flush());
@@ -1268,14 +1269,14 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveTargetLevel) {
 
   // file 1 [0 => 300]
   for (int32_t i = 0; i <= 300; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
 
   // file 2 [600 => 700]
   for (int32_t i = 600; i <= 700; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
@@ -1349,14 +1350,14 @@ TEST_P(DBCompactionTestWithParam, ManualCompactionPartial) {
 
   // file 1 [0 => 100]
   for (int32_t i = 0; i < 100; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
 
   // file 2 [100 => 300]
   for (int32_t i = 100; i < 300; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
@@ -1377,7 +1378,7 @@ TEST_P(DBCompactionTestWithParam, ManualCompactionPartial) {
 
   // file 3 [ 0 => 200]
   for (int32_t i = 0; i < 200; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
@@ -1409,21 +1410,21 @@ TEST_P(DBCompactionTestWithParam, ManualCompactionPartial) {
   TEST_SYNC_POINT("DBCompaction::ManualPartial:1");
   // file 4 [300 => 400)
   for (int32_t i = 300; i <= 400; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
 
   // file 5 [400 => 500)
   for (int32_t i = 400; i <= 500; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
 
   // file 6 [500 => 600)
   for (int32_t i = 500; i <= 600; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   // Second non-trivial compaction is triggered
@@ -1491,14 +1492,14 @@ TEST_F(DBCompactionTest, DISABLED_ManualPartialFill) {
 
   // file 1 [0 => 100]
   for (int32_t i = 0; i < 100; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
 
   // file 2 [100 => 300]
   for (int32_t i = 100; i < 300; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
@@ -1517,7 +1518,7 @@ TEST_F(DBCompactionTest, DISABLED_ManualPartialFill) {
 
   // file 3 [ 0 => 200]
   for (int32_t i = 0; i < 200; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
@@ -1549,7 +1550,7 @@ TEST_F(DBCompactionTest, DISABLED_ManualPartialFill) {
         ASSERT_OK(Flush());
         dbfull()->TEST_WaitForFlushMemTable();
       }
-      values[j] = RandomString(&rnd, value_size);
+      values[j] = rnd.RandomString(value_size);
       ASSERT_OK(Put(Key(j), values[j]));
     }
   }
@@ -1620,14 +1621,14 @@ TEST_F(DBCompactionTest, DeleteFileRange) {
 
   // file 1 [0 => 100]
   for (int32_t i = 0; i < 100; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
 
   // file 2 [100 => 300]
   for (int32_t i = 100; i < 300; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
@@ -1643,7 +1644,7 @@ TEST_F(DBCompactionTest, DeleteFileRange) {
 
   // file 3 [ 0 => 200]
   for (int32_t i = 0; i < 200; i++) {
-    values[i] = RandomString(&rnd, value_size);
+    values[i] = rnd.RandomString(value_size);
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
@@ -1655,7 +1656,7 @@ TEST_F(DBCompactionTest, DeleteFileRange) {
         ASSERT_OK(Flush());
         dbfull()->TEST_WaitForFlushMemTable();
       }
-      values[j] = RandomString(&rnd, value_size);
+      values[j] = rnd.RandomString(value_size);
       ASSERT_OK(Put(Key(j), values[j]));
     }
   }
@@ -1742,7 +1743,7 @@ TEST_F(DBCompactionTest, DeleteFilesInRanges) {
   for (auto i = 0; i < 10; i++) {
     for (auto j = 0; j < 100; j++) {
       auto k = i * 100 + j;
-      values[k] = RandomString(&rnd, value_size);
+      values[k] = rnd.RandomString(value_size);
       ASSERT_OK(Put(Key(k), values[k]));
     }
     ASSERT_OK(Flush());
@@ -1874,7 +1875,7 @@ TEST_F(DBCompactionTest, DeleteFileRangeFileEndpointsOverlapBug) {
   // would cause `1 -> vals[0]` (an older key) to reappear.
   std::string vals[kNumL0Files];
   for (int i = 0; i < kNumL0Files; ++i) {
-    vals[i] = RandomString(&rnd, kValSize);
+    vals[i] = rnd.RandomString(kValSize);
     Put(Key(i), vals[i]);
     Put(Key(i + 1), vals[i]);
     Flush();
@@ -1916,7 +1917,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveToLastLevelWithFiles) {
   std::vector<std::string> values;
   // File with keys [ 0 => 99 ]
   for (int i = 0; i < 100; i++) {
-    values.push_back(RandomString(&rnd, value_size));
+    values.push_back(rnd.RandomString(value_size));
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
@@ -1934,7 +1935,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveToLastLevelWithFiles) {
 
   // File with keys [ 100 => 199 ]
   for (int i = 100; i < 200; i++) {
-    values.push_back(RandomString(&rnd, value_size));
+    values.push_back(rnd.RandomString(value_size));
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Flush());
@@ -2329,7 +2330,7 @@ TEST_P(DBCompactionTestWithParam, ConvertCompactionStyle) {
 
   for (int i = 0; i <= max_key_level_insert; i++) {
     // each value is 10K
-    ASSERT_OK(Put(1, Key(i), RandomString(&rnd, 10000)));
+    ASSERT_OK(Put(1, Key(i), rnd.RandomString(10000)));
   }
   ASSERT_OK(Flush(1));
   dbfull()->TEST_WaitForCompact();
@@ -2387,7 +2388,7 @@ TEST_P(DBCompactionTestWithParam, ConvertCompactionStyle) {
   ReopenWithColumnFamilies({"default", "pikachu"}, options);
 
   for (int i = max_key_level_insert / 2; i <= max_key_universal_insert; i++) {
-    ASSERT_OK(Put(1, Key(i), RandomString(&rnd, 10000)));
+    ASSERT_OK(Put(1, Key(i), rnd.RandomString(10000)));
   }
   dbfull()->Flush(FlushOptions());
   ASSERT_OK(Flush(1));
@@ -2682,7 +2683,7 @@ TEST_P(DBCompactionTestWithParam, DISABLED_CompactFilesOnLevelCompaction) {
 
   Random rnd(301);
   for (int key = 64 * kEntriesPerBuffer; key >= 0; --key) {
-    ASSERT_OK(Put(1, ToString(key), RandomString(&rnd, kTestValueSize)));
+    ASSERT_OK(Put(1, ToString(key), rnd.RandomString(kTestValueSize)));
   }
   dbfull()->TEST_WaitForFlushMemTable(handles_[1]);
   dbfull()->TEST_WaitForCompact();
@@ -2758,8 +2759,8 @@ TEST_P(DBCompactionTestWithParam, PartialCompactionFailure) {
   std::vector<std::string> keys;
   std::vector<std::string> values;
   for (int k = 0; k < kNumInsertedKeys; ++k) {
-    keys.emplace_back(RandomString(&rnd, kKeySize));
-    values.emplace_back(RandomString(&rnd, kKvSize - kKeySize));
+    keys.emplace_back(rnd.RandomString(kKeySize));
+    values.emplace_back(rnd.RandomString(kKvSize - kKeySize));
     ASSERT_OK(Put(Slice(keys[k]), Slice(values[k])));
     dbfull()->TEST_WaitForFlushMemTable();
   }
@@ -2825,7 +2826,7 @@ TEST_P(DBCompactionTestWithParam, DeleteMovedFileAfterCompaction) {
     for (int i = 0; i < 2; ++i) {
       // Create 1MB sst file
       for (int j = 0; j < 100; ++j) {
-        ASSERT_OK(Put(Key(i * 50 + j), RandomString(&rnd, 10 * 1024)));
+        ASSERT_OK(Put(Key(i * 50 + j), rnd.RandomString(10 * 1024)));
       }
       ASSERT_OK(Flush());
     }
@@ -2860,7 +2861,7 @@ TEST_P(DBCompactionTestWithParam, DeleteMovedFileAfterCompaction) {
     for (int i = 0; i < 2; ++i) {
       // Create 1MB sst file
       for (int j = 0; j < 100; ++j) {
-        ASSERT_OK(Put(Key(i * 50 + j + 100), RandomString(&rnd, 10 * 1024)));
+        ASSERT_OK(Put(Key(i * 50 + j + 100), rnd.RandomString(10 * 1024)));
       }
       ASSERT_OK(Flush());
     }
@@ -3118,7 +3119,7 @@ TEST_P(DBCompactionTestWithParam, ForceBottommostLevelCompaction) {
   std::vector<std::string> values;
   // File with keys [ 0 => 99 ]
   for (int i = 0; i < 100; i++) {
-    values.push_back(RandomString(&rnd, value_size));
+    values.push_back(rnd.RandomString(value_size));
     ASSERT_OK(Put(ShortKey(i), values[i]));
   }
   ASSERT_OK(Flush());
@@ -3135,7 +3136,7 @@ TEST_P(DBCompactionTestWithParam, ForceBottommostLevelCompaction) {
 
   // File with keys [ 100 => 199 ]
   for (int i = 100; i < 200; i++) {
-    values.push_back(RandomString(&rnd, value_size));
+    values.push_back(rnd.RandomString(value_size));
     ASSERT_OK(Put(ShortKey(i), values[i]));
   }
   ASSERT_OK(Flush());
@@ -3153,7 +3154,7 @@ TEST_P(DBCompactionTestWithParam, ForceBottommostLevelCompaction) {
 
   // File with keys [ 200 => 299 ]
   for (int i = 200; i < 300; i++) {
-    values.push_back(RandomString(&rnd, value_size));
+    values.push_back(rnd.RandomString(value_size));
     ASSERT_OK(Put(ShortKey(i), values[i]));
   }
   ASSERT_OK(Flush());
@@ -3197,7 +3198,7 @@ TEST_P(DBCompactionTestWithParam, IntraL0Compaction) {
 
   const size_t kValueSize = 1 << 20;
   Random rnd(301);
-  std::string value(RandomString(&rnd, kValueSize));
+  std::string value(rnd.RandomString(kValueSize));
 
   ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->LoadDependency(
       {{"LevelCompactionPicker::PickCompactionBySize:0",
@@ -3261,7 +3262,7 @@ TEST_P(DBCompactionTestWithParam, IntraL0CompactionDoesNotObsoleteDeletions) {
 
   const size_t kValueSize = 1 << 20;
   Random rnd(301);
-  std::string value(RandomString(&rnd, kValueSize));
+  std::string value(rnd.RandomString(kValueSize));
 
   ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->LoadDependency(
       {{"LevelCompactionPicker::PickCompactionBySize:0",
@@ -3480,7 +3481,7 @@ TEST_F(DBCompactionTest, CompactBottomLevelFilesWithDeletions) {
   for (int i = 0; i < kNumLevelFiles; ++i) {
     for (int j = 0; j < kNumKeysPerFile; ++j) {
       ASSERT_OK(
-          Put(Key(i * kNumKeysPerFile + j), RandomString(&rnd, kValueSize)));
+          Put(Key(i * kNumKeysPerFile + j), rnd.RandomString(kValueSize)));
     }
     if (i == kNumLevelFiles - 1) {
       snapshot = db_->GetSnapshot();
@@ -3552,7 +3553,7 @@ TEST_F(DBCompactionTest, LevelCompactExpiredTtlFiles) {
   for (int i = 0; i < kNumLevelFiles; ++i) {
     for (int j = 0; j < kNumKeysPerFile; ++j) {
       ASSERT_OK(
-          Put(Key(i * kNumKeysPerFile + j), RandomString(&rnd, kValueSize)));
+          Put(Key(i * kNumKeysPerFile + j), rnd.RandomString(kValueSize)));
     }
     Flush();
   }
@@ -3598,7 +3599,7 @@ TEST_F(DBCompactionTest, LevelCompactExpiredTtlFiles) {
   for (int i = 0; i < kNumLevelFiles; ++i) {
     for (int j = 0; j < kNumKeysPerFile; ++j) {
       ASSERT_OK(
-          Put(Key(i * kNumKeysPerFile + j), RandomString(&rnd, kValueSize)));
+          Put(Key(i * kNumKeysPerFile + j), rnd.RandomString(kValueSize)));
     }
     Flush();
   }
@@ -3693,7 +3694,7 @@ TEST_F(DBCompactionTest, LevelTtlCascadingCompactions) {
       // Add two L6 files with key ranges: [1 .. 100], [101 .. 200].
       Random rnd(301);
       for (int i = 1; i <= 100; ++i) {
-        ASSERT_OK(Put(Key(i), RandomString(&rnd, kValueSize)));
+        ASSERT_OK(Put(Key(i), rnd.RandomString(kValueSize)));
       }
       Flush();
       // Get the first file's creation time. This will be the oldest file in the
@@ -3706,7 +3707,7 @@ TEST_F(DBCompactionTest, LevelTtlCascadingCompactions) {
       // Add 1 hour and do another flush.
       env_->addon_time_.fetch_add(1 * 60 * 60);
       for (int i = 101; i <= 200; ++i) {
-        ASSERT_OK(Put(Key(i), RandomString(&rnd, kValueSize)));
+        ASSERT_OK(Put(Key(i), rnd.RandomString(kValueSize)));
       }
       Flush();
       MoveFilesToLevel(6);
@@ -3715,12 +3716,12 @@ TEST_F(DBCompactionTest, LevelTtlCascadingCompactions) {
       env_->addon_time_.fetch_add(1 * 60 * 60);
       // Add two L4 files with key ranges: [1 .. 50], [51 .. 150].
       for (int i = 1; i <= 50; ++i) {
-        ASSERT_OK(Put(Key(i), RandomString(&rnd, kValueSize)));
+        ASSERT_OK(Put(Key(i), rnd.RandomString(kValueSize)));
       }
       Flush();
       env_->addon_time_.fetch_add(1 * 60 * 60);
       for (int i = 51; i <= 150; ++i) {
-        ASSERT_OK(Put(Key(i), RandomString(&rnd, kValueSize)));
+        ASSERT_OK(Put(Key(i), rnd.RandomString(kValueSize)));
       }
       Flush();
       MoveFilesToLevel(4);
@@ -3729,7 +3730,7 @@ TEST_F(DBCompactionTest, LevelTtlCascadingCompactions) {
       env_->addon_time_.fetch_add(1 * 60 * 60);
       // Add one L1 file with key range: [26, 75].
       for (int i = 26; i <= 75; ++i) {
-        ASSERT_OK(Put(Key(i), RandomString(&rnd, kValueSize)));
+        ASSERT_OK(Put(Key(i), rnd.RandomString(kValueSize)));
       }
       Flush();
       dbfull()->TEST_WaitForCompact();
@@ -3840,8 +3841,8 @@ TEST_F(DBCompactionTest, LevelPeriodicCompaction) {
       Random rnd(301);
       for (int i = 0; i < kNumLevelFiles; ++i) {
         for (int j = 0; j < kNumKeysPerFile; ++j) {
-          ASSERT_OK(Put(Key(i * kNumKeysPerFile + j),
-                        RandomString(&rnd, kValueSize)));
+          ASSERT_OK(
+              Put(Key(i * kNumKeysPerFile + j), rnd.RandomString(kValueSize)));
         }
         Flush();
       }
@@ -3935,7 +3936,7 @@ TEST_F(DBCompactionTest, LevelPeriodicCompactionWithOldDB) {
   for (int i = 0; i < kNumFiles; ++i) {
     for (int j = 0; j < kNumKeysPerFile; ++j) {
       ASSERT_OK(
-          Put(Key(i * kNumKeysPerFile + j), RandomString(&rnd, kValueSize)));
+          Put(Key(i * kNumKeysPerFile + j), rnd.RandomString(kValueSize)));
     }
     Flush();
     // Move the first two files to L2.
@@ -3998,7 +3999,7 @@ TEST_F(DBCompactionTest, LevelPeriodicAndTtlCompaction) {
   for (int i = 0; i < kNumLevelFiles; ++i) {
     for (int j = 0; j < kNumKeysPerFile; ++j) {
       ASSERT_OK(
-          Put(Key(i * kNumKeysPerFile + j), RandomString(&rnd, kValueSize)));
+          Put(Key(i * kNumKeysPerFile + j), rnd.RandomString(kValueSize)));
     }
     Flush();
   }
@@ -4109,7 +4110,7 @@ TEST_F(DBCompactionTest, LevelPeriodicCompactionWithCompactionFilters) {
     for (int i = 0; i < kNumLevelFiles; ++i) {
       for (int j = 0; j < kNumKeysPerFile; ++j) {
         ASSERT_OK(
-            Put(Key(i * kNumKeysPerFile + j), RandomString(&rnd, kValueSize)));
+            Put(Key(i * kNumKeysPerFile + j), rnd.RandomString(kValueSize)));
       }
       Flush();
     }
@@ -4169,7 +4170,7 @@ TEST_F(DBCompactionTest, CompactRangeDelayedByL0FileCount) {
     Random rnd(301);
     for (int j = 0; j < kNumL0FilesLimit - 1; ++j) {
       for (int k = 0; k < 2; ++k) {
-        ASSERT_OK(Put(Key(k), RandomString(&rnd, 1024)));
+        ASSERT_OK(Put(Key(k), rnd.RandomString(1024)));
       }
       Flush();
     }
@@ -4223,7 +4224,7 @@ TEST_F(DBCompactionTest, CompactRangeDelayedByImmMemTableCount) {
 
     Random rnd(301);
     for (int j = 0; j < kNumImmMemTableLimit - 1; ++j) {
-      ASSERT_OK(Put(Key(0), RandomString(&rnd, 1024)));
+      ASSERT_OK(Put(Key(0), rnd.RandomString(1024)));
       FlushOptions flush_opts;
       flush_opts.wait = false;
       flush_opts.allow_write_stall = true;
@@ -4271,7 +4272,7 @@ TEST_F(DBCompactionTest, CompactRangeShutdownWhileDelayed) {
     Random rnd(301);
     for (int j = 0; j < kNumL0FilesLimit - 1; ++j) {
       for (int k = 0; k < 2; ++k) {
-        ASSERT_OK(Put(1, Key(k), RandomString(&rnd, 1024)));
+        ASSERT_OK(Put(1, Key(k), rnd.RandomString(1024)));
       }
       Flush(1);
     }
@@ -4331,7 +4332,7 @@ TEST_F(DBCompactionTest, CompactRangeSkipFlushAfterDelay) {
   flush_opts.allow_write_stall = true;
   for (int i = 0; i < kNumL0FilesLimit - 1; ++i) {
     for (int j = 0; j < 2; ++j) {
-      ASSERT_OK(Put(Key(j), RandomString(&rnd, 1024)));
+      ASSERT_OK(Put(Key(j), rnd.RandomString(1024)));
     }
     dbfull()->Flush(flush_opts);
   }
@@ -4342,9 +4343,9 @@ TEST_F(DBCompactionTest, CompactRangeSkipFlushAfterDelay) {
   });
 
   TEST_SYNC_POINT("DBCompactionTest::CompactRangeSkipFlushAfterDelay:PreFlush");
-  Put(ToString(0), RandomString(&rnd, 1024));
+  Put(ToString(0), rnd.RandomString(1024));
   dbfull()->Flush(flush_opts);
-  Put(ToString(0), RandomString(&rnd, 1024));
+  Put(ToString(0), rnd.RandomString(1024));
   TEST_SYNC_POINT("DBCompactionTest::CompactRangeSkipFlushAfterDelay:PostFlush");
   manual_compaction_thread.join();
 
@@ -4784,7 +4785,7 @@ TEST_P(CompactionPriTest, Test) {
   RandomShuffle(std::begin(keys), std::end(keys), rnd.Next());
 
   for (int i = 0; i < kNKeys; i++) {
-    ASSERT_OK(Put(Key(keys[i]), RandomString(&rnd, 102)));
+    ASSERT_OK(Put(Key(keys[i]), rnd.RandomString(102)));
   }
 
   dbfull()->TEST_WaitForCompact();
@@ -4826,7 +4827,7 @@ TEST_F(DBCompactionTest, PartialManualCompaction) {
   Random rnd(301);
   for (auto i = 0; i < 8; ++i) {
     for (auto j = 0; j < 10; ++j) {
-      Merge("foo", RandomString(&rnd, 1024));
+      Merge("foo", rnd.RandomString(1024));
     }
     Flush();
   }
@@ -4858,8 +4859,8 @@ TEST_F(DBCompactionTest, ManualCompactionFailsInReadOnlyMode) {
   Random rnd(301);
   for (int i = 0; i < kNumL0Files; ++i) {
     // Make sure files are overlapping in key-range to prevent trivial move.
-    Put("key1", RandomString(&rnd, 1024));
-    Put("key2", RandomString(&rnd, 1024));
+    Put("key1", rnd.RandomString(1024));
+    Put("key2", rnd.RandomString(1024));
     Flush();
   }
   ASSERT_EQ(kNumL0Files, NumTableFilesAtLevel(0));
@@ -4868,7 +4869,7 @@ TEST_F(DBCompactionTest, ManualCompactionFailsInReadOnlyMode) {
   mock_env->SetFilesystemActive(false);
   // Make sure this is outside `CompactRange`'s range so that it doesn't fail
   // early trying to flush memtable.
-  ASSERT_NOK(Put("key3", RandomString(&rnd, 1024)));
+  ASSERT_NOK(Put("key3", rnd.RandomString(1024)));
 
   // In the bug scenario, the first manual compaction would fail and forget to
   // unregister itself, causing the second one to hang forever due to conflict
@@ -4907,7 +4908,7 @@ TEST_F(DBCompactionTest, ManualCompactionBottomLevelOptimized) {
   for (auto i = 0; i < 8; ++i) {
     for (auto j = 0; j < 10; ++j) {
       ASSERT_OK(
-          Put("foo" + std::to_string(i * 10 + j), RandomString(&rnd, 1024)));
+          Put("foo" + std::to_string(i * 10 + j), rnd.RandomString(1024)));
     }
     Flush();
   }
@@ -4917,7 +4918,7 @@ TEST_F(DBCompactionTest, ManualCompactionBottomLevelOptimized) {
   for (auto i = 0; i < 8; ++i) {
     for (auto j = 0; j < 10; ++j) {
       ASSERT_OK(
-          Put("bar" + std::to_string(i * 10 + j), RandomString(&rnd, 1024)));
+          Put("bar" + std::to_string(i * 10 + j), rnd.RandomString(1024)));
     }
     Flush();
   }
@@ -4951,7 +4952,7 @@ TEST_F(DBCompactionTest, CompactionDuringShutdown) {
   for (auto i = 0; i < 2; ++i) {
     for (auto j = 0; j < 10; ++j) {
       ASSERT_OK(
-          Put("foo" + std::to_string(i * 10 + j), RandomString(&rnd, 1024)));
+          Put("foo" + std::to_string(i * 10 + j), rnd.RandomString(1024)));
     }
     Flush();
   }
@@ -4974,7 +4975,7 @@ TEST_P(DBCompactionTestWithParam, FixFileIngestionCompactionDeadlock) {
 
   // Generate an external SST file containing a single key, i.e. 99
   std::string sst_files_dir = dbname_ + "/sst_files/";
-  test::DestroyDir(env_, sst_files_dir);
+  DestroyDir(env_, sst_files_dir);
   ASSERT_OK(env_->CreateDir(sst_files_dir));
   SstFileWriter sst_writer(EnvOptions(), options);
   const std::string sst_file_path = sst_files_dir + "test.sst";
@@ -5001,7 +5002,7 @@ TEST_P(DBCompactionTestWithParam, FixFileIngestionCompactionDeadlock) {
   // Generate level0_stop_writes_trigger L0 files to trigger write stop
   for (int i = 0; i != options.level0_file_num_compaction_trigger; ++i) {
     for (int j = 0; j != kNumKeysPerFile; ++j) {
-      ASSERT_OK(Put(Key(j), RandomString(&rnd, 990)));
+      ASSERT_OK(Put(Key(j), rnd.RandomString(990)));
     }
     if (0 == i) {
       // When we reach here, the memtables have kNumKeysPerFile keys. Note that
@@ -5093,7 +5094,7 @@ TEST_F(DBCompactionTest, ConsistencyFailTest2) {
   ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
 
   Random rnd(301);
-  std::string value = RandomString(&rnd, 1000);
+  std::string value = rnd.RandomString(1000);
 
   ASSERT_OK(Put("foo1", value));
   ASSERT_OK(Put("z", ""));
@@ -5140,7 +5141,7 @@ TEST_P(DBCompactionTestWithParam,
   const size_t kValueSize = 1 << 20;
   Random rnd(301);
   std::atomic<int> pick_intra_l0_count(0);
-  std::string value(RandomString(&rnd, kValueSize));
+  std::string value(rnd.RandomString(kValueSize));
 
   ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->LoadDependency(
       {{"DBCompactionTestWithParam::FlushAfterIntraL0:1",
@@ -5207,8 +5208,8 @@ TEST_P(DBCompactionTestWithParam,
 
   const size_t kValueSize = 1 << 20;
   Random rnd(301);
-  std::string value(RandomString(&rnd, kValueSize));
-  std::string value2(RandomString(&rnd, kValueSize));
+  std::string value(rnd.RandomString(kValueSize));
+  std::string value2(rnd.RandomString(kValueSize));
   std::string bigvalue = value + value;
 
   // prevents trivial move
diff --git a/db/db_dynamic_level_test.cc b/db/db_dynamic_level_test.cc
index ec059feb9..4273354ae 100644
--- a/db/db_dynamic_level_test.cc
+++ b/db/db_dynamic_level_test.cc
@@ -15,6 +15,7 @@
 #include "db/db_test_util.h"
 #include "port/port.h"
 #include "port/stack_trace.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 class DBTestDynamicLevel : public DBTestBase {
@@ -80,9 +81,9 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesBase) {
 
       for (int i = 0; i < kNKeys; i++) {
         int key = keys[i];
-        ASSERT_OK(Put(Key(kNKeys + key), RandomString(&rnd, 102)));
-        ASSERT_OK(Put(Key(key), RandomString(&rnd, 102)));
-        ASSERT_OK(Put(Key(kNKeys * 2 + key), RandomString(&rnd, 102)));
+        ASSERT_OK(Put(Key(kNKeys + key), rnd.RandomString(102)));
+        ASSERT_OK(Put(Key(key), rnd.RandomString(102)));
+        ASSERT_OK(Put(Key(kNKeys * 2 + key), rnd.RandomString(102)));
         ASSERT_OK(Delete(Key(kNKeys + keys[i / 10])));
         env_->SleepForMicroseconds(5000);
       }
@@ -158,7 +159,7 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesBase2) {
   // Put about 28K to L0
   for (int i = 0; i < 70; i++) {
     ASSERT_OK(Put(Key(static_cast<int>(rnd.Uniform(kMaxKey))),
-                  RandomString(&rnd, 380)));
+                  rnd.RandomString(380)));
   }
   ASSERT_OK(dbfull()->SetOptions({
       {"disable_auto_compactions", "false"},
@@ -175,7 +176,7 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesBase2) {
   }));
   for (int i = 0; i < 70; i++) {
     ASSERT_OK(Put(Key(static_cast<int>(rnd.Uniform(kMaxKey))),
-                  RandomString(&rnd, 380)));
+                  rnd.RandomString(380)));
   }
 
   ASSERT_OK(dbfull()->SetOptions({
@@ -197,7 +198,7 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesBase2) {
   // Write about 40K more
   for (int i = 0; i < 100; i++) {
     ASSERT_OK(Put(Key(static_cast<int>(rnd.Uniform(kMaxKey))),
-                  RandomString(&rnd, 380)));
+                  rnd.RandomString(380)));
   }
   ASSERT_OK(dbfull()->SetOptions({
       {"disable_auto_compactions", "false"},
@@ -216,7 +217,7 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesBase2) {
   // Each file is about 11KB, with 9KB of data.
   for (int i = 0; i < 1300; i++) {
     ASSERT_OK(Put(Key(static_cast<int>(rnd.Uniform(kMaxKey))),
-                  RandomString(&rnd, 380)));
+                  rnd.RandomString(380)));
   }
 
   // Make sure that the compaction starts before the last bit of data is
@@ -257,7 +258,7 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesBase2) {
   TEST_SYNC_POINT("DynamicLevelMaxBytesBase2:1");
   for (int i = 0; i < 2; i++) {
     ASSERT_OK(Put(Key(static_cast<int>(rnd.Uniform(kMaxKey))),
-                  RandomString(&rnd, 380)));
+                  rnd.RandomString(380)));
   }
   TEST_SYNC_POINT("DynamicLevelMaxBytesBase2:2");
 
@@ -310,15 +311,15 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesCompactRange) {
 
   // Put about 7K to L0
   for (int i = 0; i < 140; i++) {
-    ASSERT_OK(Put(Key(static_cast<int>(rnd.Uniform(kMaxKey))),
-                  RandomString(&rnd, 80)));
+    ASSERT_OK(
+        Put(Key(static_cast<int>(rnd.Uniform(kMaxKey))), rnd.RandomString(80)));
   }
   Flush();
   dbfull()->TEST_WaitForCompact();
   if (NumTableFilesAtLevel(0) == 0) {
     // Make sure level 0 is not empty
-    ASSERT_OK(Put(Key(static_cast<int>(rnd.Uniform(kMaxKey))),
-                  RandomString(&rnd, 80)));
+    ASSERT_OK(
+        Put(Key(static_cast<int>(rnd.Uniform(kMaxKey))), rnd.RandomString(80)));
     Flush();
   }
 
@@ -382,7 +383,7 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesBaseInc) {
   const int total_keys = 3000;
   const int random_part_size = 100;
   for (int i = 0; i < total_keys; i++) {
-    std::string value = RandomString(&rnd, random_part_size);
+    std::string value = rnd.RandomString(random_part_size);
     PutFixed32(&value, static_cast<uint32_t>(i));
     ASSERT_OK(Put(Key(i), value));
   }
@@ -441,8 +442,8 @@ TEST_F(DBTestDynamicLevel, DISABLED_MigrateToDynamicLevelMaxBytesBase) {
 
   int total_keys = 1000;
   for (int i = 0; i < total_keys; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 102)));
-    ASSERT_OK(Put(Key(kMaxKey + i), RandomString(&rnd, 102)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(102)));
+    ASSERT_OK(Put(Key(kMaxKey + i), rnd.RandomString(102)));
     ASSERT_OK(Delete(Key(i / 10)));
   }
   verify_func(total_keys, false);
@@ -475,8 +476,8 @@ TEST_F(DBTestDynamicLevel, DISABLED_MigrateToDynamicLevelMaxBytesBase) {
 
   int total_keys2 = 2000;
   for (int i = total_keys; i < total_keys2; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 102)));
-    ASSERT_OK(Put(Key(kMaxKey + i), RandomString(&rnd, 102)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(102)));
+    ASSERT_OK(Put(Key(kMaxKey + i), rnd.RandomString(102)));
     ASSERT_OK(Delete(Key(i / 10)));
   }
 
diff --git a/db/db_flush_test.cc b/db/db_flush_test.cc
index 6255bbd51..0a0914484 100644
--- a/db/db_flush_test.cc
+++ b/db/db_flush_test.cc
@@ -13,10 +13,10 @@
 #include "db/db_test_util.h"
 #include "port/port.h"
 #include "port/stack_trace.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/sync_point.h"
 #include "util/cast_util.h"
 #include "util/mutexlock.h"
+#include "utilities/fault_injection_env.h"
 
 namespace ROCKSDB_NAMESPACE {
 
diff --git a/db/db_impl/db_secondary_test.cc b/db/db_impl/db_secondary_test.cc
index d54a52493..00284b1a4 100644
--- a/db/db_impl/db_secondary_test.cc
+++ b/db/db_impl/db_secondary_test.cc
@@ -10,8 +10,8 @@
 #include "db/db_impl/db_impl_secondary.h"
 #include "db/db_test_util.h"
 #include "port/stack_trace.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/sync_point.h"
+#include "utilities/fault_injection_env.h"
 
 namespace ROCKSDB_NAMESPACE {
 
diff --git a/db/db_io_failure_test.cc b/db/db_io_failure_test.cc
index f8d562447..42b4c3476 100644
--- a/db/db_io_failure_test.cc
+++ b/db/db_io_failure_test.cc
@@ -9,6 +9,7 @@
 
 #include "db/db_test_util.h"
 #include "port/stack_trace.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -281,8 +282,8 @@ TEST_F(DBIOFailureTest, FlushSstRangeSyncError) {
 
   Random rnd(301);
   std::string rnd_str =
-      RandomString(&rnd, static_cast<int>(options.bytes_per_sync / 2));
-  std::string rnd_str_512kb = RandomString(&rnd, 512 * 1024);
+      rnd.RandomString(static_cast<int>(options.bytes_per_sync / 2));
+  std::string rnd_str_512kb = rnd.RandomString(512 * 1024);
 
   ASSERT_OK(Put(1, "foo", "bar"));
   // First 1MB doesn't get range synced
@@ -330,8 +331,8 @@ TEST_F(DBIOFailureTest, CompactSstRangeSyncError) {
 
   Random rnd(301);
   std::string rnd_str =
-      RandomString(&rnd, static_cast<int>(options.bytes_per_sync / 2));
-  std::string rnd_str_512kb = RandomString(&rnd, 512 * 1024);
+      rnd.RandomString(static_cast<int>(options.bytes_per_sync / 2));
+  std::string rnd_str_512kb = rnd.RandomString(512 * 1024);
 
   ASSERT_OK(Put(1, "foo", "bar"));
   // First 1MB doesn't get range synced
diff --git a/db/db_iterator_test.cc b/db/db_iterator_test.cc
index 6d06fa6ea..968511b1f 100644
--- a/db/db_iterator_test.cc
+++ b/db/db_iterator_test.cc
@@ -17,6 +17,7 @@
 #include "rocksdb/iostats_context.h"
 #include "rocksdb/perf_context.h"
 #include "table/block_based/flush_block_policy.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -194,10 +195,10 @@ TEST_P(DBIteratorTest, IterReseekNewUpperBound) {
   options.compression = kNoCompression;
   Reopen(options);
 
-  ASSERT_OK(Put("a", RandomString(&rnd, 400)));
-  ASSERT_OK(Put("aabb", RandomString(&rnd, 400)));
-  ASSERT_OK(Put("aaef", RandomString(&rnd, 400)));
-  ASSERT_OK(Put("b", RandomString(&rnd, 400)));
+  ASSERT_OK(Put("a", rnd.RandomString(400)));
+  ASSERT_OK(Put("aabb", rnd.RandomString(400)));
+  ASSERT_OK(Put("aaef", rnd.RandomString(400)));
+  ASSERT_OK(Put("b", rnd.RandomString(400)));
   dbfull()->Flush(FlushOptions());
   ReadOptions opts;
   Slice ub = Slice("aa");
@@ -1360,7 +1361,7 @@ class DBIteratorTestForPinnedData : public DBIteratorTest {
 
     std::vector<std::string> generated_keys(key_pool);
     for (int i = 0; i < key_pool; i++) {
-      generated_keys[i] = RandomString(&rnd, key_size);
+      generated_keys[i] = rnd.RandomString(key_size);
     }
 
     std::map<std::string, std::string> true_data;
@@ -1368,7 +1369,7 @@ class DBIteratorTestForPinnedData : public DBIteratorTest {
     std::vector<std::string> deleted_keys;
     for (int i = 0; i < puts; i++) {
       auto& k = generated_keys[rnd.Next() % key_pool];
-      auto v = RandomString(&rnd, val_size);
+      auto v = rnd.RandomString(val_size);
 
       // Insert data to true_data map and to DB
       true_data[k] = v;
@@ -1531,7 +1532,7 @@ TEST_P(DBIteratorTest, PinnedDataIteratorMultipleFiles) {
   Random rnd(301);
   for (int i = 1; i <= 1000; i++) {
     std::string k = Key(i * 3);
-    std::string v = RandomString(&rnd, 100);
+    std::string v = rnd.RandomString(100);
     ASSERT_OK(Put(k, v));
     true_data[k] = v;
     if (i % 250 == 0) {
@@ -1545,7 +1546,7 @@ TEST_P(DBIteratorTest, PinnedDataIteratorMultipleFiles) {
   // Generate 4 sst files in L0
   for (int i = 1; i <= 1000; i++) {
     std::string k = Key(i * 2);
-    std::string v = RandomString(&rnd, 100);
+    std::string v = rnd.RandomString(100);
     ASSERT_OK(Put(k, v));
     true_data[k] = v;
     if (i % 250 == 0) {
@@ -1557,7 +1558,7 @@ TEST_P(DBIteratorTest, PinnedDataIteratorMultipleFiles) {
   // Add some keys/values in memtables
   for (int i = 1; i <= 1000; i++) {
     std::string k = Key(i);
-    std::string v = RandomString(&rnd, 100);
+    std::string v = rnd.RandomString(100);
     ASSERT_OK(Put(k, v));
     true_data[k] = v;
   }
@@ -1659,8 +1660,8 @@ TEST_P(DBIteratorTest, PinnedDataIteratorReadAfterUpdate) {
 
   std::map<std::string, std::string> true_data;
   for (int i = 0; i < 1000; i++) {
-    std::string k = RandomString(&rnd, 10);
-    std::string v = RandomString(&rnd, 1000);
+    std::string k = rnd.RandomString(10);
+    std::string v = rnd.RandomString(1000);
     ASSERT_OK(Put(k, v));
     true_data[k] = v;
   }
@@ -1674,7 +1675,7 @@ TEST_P(DBIteratorTest, PinnedDataIteratorReadAfterUpdate) {
     if (rnd.OneIn(2)) {
       ASSERT_OK(Delete(kv.first));
     } else {
-      std::string new_val = RandomString(&rnd, 1000);
+      std::string new_val = rnd.RandomString(1000);
       ASSERT_OK(Put(kv.first, new_val));
     }
   }
@@ -1931,7 +1932,7 @@ TEST_P(DBIteratorTest, IterPrevKeyCrossingBlocksRandomized) {
 
   for (int i = 0; i < kNumKeys; i++) {
     gen_key = Key(i);
-    gen_val = RandomString(&rnd, kValSize);
+    gen_val = rnd.RandomString(kValSize);
 
     ASSERT_OK(Put(gen_key, gen_val));
     true_data[gen_key] = gen_val;
@@ -1949,7 +1950,7 @@ TEST_P(DBIteratorTest, IterPrevKeyCrossingBlocksRandomized) {
 
     for (int j = 0; j < kNumMergeOperands; j++) {
       gen_key = Key(i);
-      gen_val = RandomString(&rnd, kValSize);
+      gen_val = rnd.RandomString(kValSize);
 
       ASSERT_OK(db_->Merge(WriteOptions(), gen_key, gen_val));
       true_data[gen_key] += "," + gen_val;
@@ -2049,7 +2050,7 @@ TEST_P(DBIteratorTest, IteratorWithLocalStatistics) {
   Random rnd(301);
   for (int i = 0; i < 1000; i++) {
     // Key 10 bytes / Value 10 bytes
-    ASSERT_OK(Put(RandomString(&rnd, 10), RandomString(&rnd, 10)));
+    ASSERT_OK(Put(rnd.RandomString(10), rnd.RandomString(10)));
   }
 
   std::atomic<uint64_t> total_next(0);
@@ -2705,7 +2706,7 @@ TEST_P(DBIteratorTest, AvoidReseekLevelIterator) {
   Reopen(options);
 
   Random rnd(301);
-  std::string random_str = RandomString(&rnd, 180);
+  std::string random_str = rnd.RandomString(180);
 
   ASSERT_OK(Put("1", random_str));
   ASSERT_OK(Put("2", random_str));
diff --git a/db/db_merge_operand_test.cc b/db/db_merge_operand_test.cc
index a0ab34e01..555bec090 100644
--- a/db/db_merge_operand_test.cc
+++ b/db/db_merge_operand_test.cc
@@ -8,11 +8,11 @@
 #include "rocksdb/perf_context.h"
 #include "rocksdb/utilities/debug.h"
 #include "table/block_based/block_builder.h"
-#include "test_util/fault_injection_test_env.h"
 #if !defined(ROCKSDB_LITE)
 #include "test_util/sync_point.h"
 #endif
 #include "rocksdb/merge_operator.h"
+#include "utilities/fault_injection_env.h"
 #include "utilities/merge_operators.h"
 #include "utilities/merge_operators/sortlist.h"
 #include "utilities/merge_operators/string_append/stringappend2.h"
diff --git a/db/db_merge_operator_test.cc b/db/db_merge_operator_test.cc
index 4f762468d..616d27671 100644
--- a/db/db_merge_operator_test.cc
+++ b/db/db_merge_operator_test.cc
@@ -9,6 +9,7 @@
 #include "db/forward_iterator.h"
 #include "port/stack_trace.h"
 #include "rocksdb/merge_operator.h"
+#include "util/random.h"
 #include "utilities/merge_operators.h"
 #include "utilities/merge_operators/string_append/stringappend2.h"
 
@@ -242,7 +243,7 @@ TEST_P(MergeOperatorPinningTest, OperandsMultiBlocks) {
       std::string key = Key(key_id % 35);
       key_id++;
       for (int k = 0; k < kOperandsPerKeyPerFile; k++) {
-        std::string val = RandomString(&rnd, kOperandSize);
+        std::string val = rnd.RandomString(kOperandSize);
         ASSERT_OK(db_->Merge(WriteOptions(), key, val));
         if (true_data[key].size() == 0) {
           true_data[key] = val;
@@ -327,7 +328,7 @@ TEST_P(MergeOperatorPinningTest, EvictCacheBeforeMerge) {
   for (int i = 0; i < kNumOperands; i++) {
     for (int j = 0; j < kNumKeys; j++) {
       std::string k = Key(j);
-      std::string v = RandomString(&rnd, kOperandSize);
+      std::string v = rnd.RandomString(kOperandSize);
       ASSERT_OK(db_->Merge(WriteOptions(), k, v));
 
       true_data[k] = std::max(true_data[k], v);
@@ -620,7 +621,7 @@ TEST_P(PerConfigMergeOperatorPinningTest, Randomized) {
   // kNumPutBefore keys will have base values
   for (int i = 0; i < kNumPutBefore; i++) {
     std::string key = Key(rnd.Next() % kKeyRange);
-    std::string value = RandomString(&rnd, kOperandSize);
+    std::string value = rnd.RandomString(kOperandSize);
     ASSERT_OK(db_->Put(WriteOptions(), key, value));
 
     true_data[key] = value;
@@ -629,7 +630,7 @@ TEST_P(PerConfigMergeOperatorPinningTest, Randomized) {
   // Do kTotalMerges merges
   for (int i = 0; i < kTotalMerges; i++) {
     std::string key = Key(rnd.Next() % kKeyRange);
-    std::string value = RandomString(&rnd, kOperandSize);
+    std::string value = rnd.RandomString(kOperandSize);
     ASSERT_OK(db_->Merge(WriteOptions(), key, value));
 
     if (true_data[key] < value) {
@@ -640,7 +641,7 @@ TEST_P(PerConfigMergeOperatorPinningTest, Randomized) {
   // Overwrite random kNumPutAfter keys
   for (int i = 0; i < kNumPutAfter; i++) {
     std::string key = Key(rnd.Next() % kKeyRange);
-    std::string value = RandomString(&rnd, kOperandSize);
+    std::string value = rnd.RandomString(kOperandSize);
     ASSERT_OK(db_->Put(WriteOptions(), key, value));
 
     true_data[key] = value;
diff --git a/db/db_options_test.cc b/db/db_options_test.cc
index 8cc09ec54..8d61ee883 100644
--- a/db/db_options_test.cc
+++ b/db/db_options_test.cc
@@ -493,8 +493,7 @@ TEST_F(DBOptionsTest, SetDelayedWriteRateOption) {
 TEST_F(DBOptionsTest, MaxTotalWalSizeChange) {
   Random rnd(1044);
   const auto value_size = size_t(1024);
-  std::string value;
-  test::RandomString(&rnd, value_size, &value);
+  std::string value = rnd.RandomString(value_size);
 
   Options options;
   options.create_if_missing = true;
@@ -715,7 +714,7 @@ TEST_F(DBOptionsTest, SetFIFOCompactionOptions) {
   for (int i = 0; i < 10; i++) {
     // Generate and flush a file about 10KB.
     for (int j = 0; j < 10; j++) {
-      ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+      ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
     }
     Flush();
   }
@@ -746,7 +745,7 @@ TEST_F(DBOptionsTest, SetFIFOCompactionOptions) {
   for (int i = 0; i < 10; i++) {
     // Generate and flush a file about 10KB.
     for (int j = 0; j < 10; j++) {
-      ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+      ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
     }
     Flush();
   }
@@ -778,7 +777,7 @@ TEST_F(DBOptionsTest, SetFIFOCompactionOptions) {
   for (int i = 0; i < 10; i++) {
     // Generate and flush a file about 10KB.
     for (int j = 0; j < 10; j++) {
-      ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+      ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
     }
     Flush();
   }
@@ -842,7 +841,7 @@ TEST_F(DBOptionsTest, FIFOTtlBackwardCompatible) {
   for (int i = 0; i < 10; i++) {
     // Generate and flush a file about 10KB.
     for (int j = 0; j < 10; j++) {
-      ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+      ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
     }
     Flush();
   }
diff --git a/db/db_properties_test.cc b/db/db_properties_test.cc
index 50dc3efef..c7baed920 100644
--- a/db/db_properties_test.cc
+++ b/db/db_properties_test.cc
@@ -126,8 +126,8 @@ TEST_F(DBPropertiesTest, GetAggregatedIntPropertyTest) {
   Random rnd(301);
   for (auto* handle : handles_) {
     for (int i = 0; i < kKeyNum; ++i) {
-      db_->Put(WriteOptions(), handle, RandomString(&rnd, kKeySize),
-               RandomString(&rnd, kValueSize));
+      db_->Put(WriteOptions(), handle, rnd.RandomString(kKeySize),
+               rnd.RandomString(kValueSize));
     }
   }
 
@@ -346,18 +346,18 @@ TEST_F(DBPropertiesTest, AggregatedTableProperties) {
     Random rnd(5632);
     for (int table = 1; table <= kTableCount; ++table) {
       for (int i = 0; i < kPutsPerTable; ++i) {
-        db_->Put(WriteOptions(), RandomString(&rnd, kKeySize),
-                 RandomString(&rnd, kValueSize));
+        db_->Put(WriteOptions(), rnd.RandomString(kKeySize),
+                 rnd.RandomString(kValueSize));
       }
       for (int i = 0; i < kDeletionsPerTable; i++) {
-        db_->Delete(WriteOptions(), RandomString(&rnd, kKeySize));
+        db_->Delete(WriteOptions(), rnd.RandomString(kKeySize));
       }
       for (int i = 0; i < kMergeOperandsPerTable; i++) {
-        db_->Merge(WriteOptions(), RandomString(&rnd, kKeySize),
-                   RandomString(&rnd, kValueSize));
+        db_->Merge(WriteOptions(), rnd.RandomString(kKeySize),
+                   rnd.RandomString(kValueSize));
       }
       for (int i = 0; i < kRangeDeletionsPerTable; i++) {
-        std::string start = RandomString(&rnd, kKeySize);
+        std::string start = rnd.RandomString(kKeySize);
         std::string end = start;
         end.resize(kValueSize);
         db_->DeleteRange(WriteOptions(), db_->DefaultColumnFamily(), start, end);
@@ -546,18 +546,18 @@ TEST_F(DBPropertiesTest, AggregatedTablePropertiesAtLevel) {
   TableProperties tp, sum_tp, expected_tp;
   for (int table = 1; table <= kTableCount; ++table) {
     for (int i = 0; i < kPutsPerTable; ++i) {
-      db_->Put(WriteOptions(), RandomString(&rnd, kKeySize),
-               RandomString(&rnd, kValueSize));
+      db_->Put(WriteOptions(), rnd.RandomString(kKeySize),
+               rnd.RandomString(kValueSize));
     }
     for (int i = 0; i < kDeletionsPerTable; i++) {
-      db_->Delete(WriteOptions(), RandomString(&rnd, kKeySize));
+      db_->Delete(WriteOptions(), rnd.RandomString(kKeySize));
     }
     for (int i = 0; i < kMergeOperandsPerTable; i++) {
-      db_->Merge(WriteOptions(), RandomString(&rnd, kKeySize),
-                 RandomString(&rnd, kValueSize));
+      db_->Merge(WriteOptions(), rnd.RandomString(kKeySize),
+                 rnd.RandomString(kValueSize));
     }
     for (int i = 0; i < kRangeDeletionsPerTable; i++) {
-      std::string start = RandomString(&rnd, kKeySize);
+      std::string start = rnd.RandomString(kKeySize);
       std::string end = start;
       end.resize(kValueSize);
       db_->DeleteRange(WriteOptions(), db_->DefaultColumnFamily(), start, end);
@@ -920,7 +920,7 @@ TEST_F(DBPropertiesTest, ApproximateMemoryUsage) {
   for (int r = 0; r < kNumRounds; ++r) {
     for (int f = 0; f < kFlushesPerRound; ++f) {
       for (int w = 0; w < kWritesPerFlush; ++w) {
-        Put(RandomString(&rnd, kKeySize), RandomString(&rnd, kValueSize));
+        Put(rnd.RandomString(kKeySize), rnd.RandomString(kValueSize));
       }
     }
     // Make sure that there is no flush between getting the two properties.
@@ -938,7 +938,7 @@ TEST_F(DBPropertiesTest, ApproximateMemoryUsage) {
     iters.push_back(db_->NewIterator(ReadOptions()));
     for (int f = 0; f < kFlushesPerRound; ++f) {
       for (int w = 0; w < kWritesPerFlush; ++w) {
-        Put(RandomString(&rnd, kKeySize), RandomString(&rnd, kValueSize));
+        Put(rnd.RandomString(kKeySize), rnd.RandomString(kValueSize));
       }
     }
     // Force flush to prevent flush from happening between getting the
@@ -1296,8 +1296,8 @@ TEST_F(DBPropertiesTest, TablePropertiesNeedCompactTest) {
 
   const int kMaxKey = 1000;
   for (int i = 0; i < kMaxKey; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 102)));
-    ASSERT_OK(Put(Key(kMaxKey + i), RandomString(&rnd, 102)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(102)));
+    ASSERT_OK(Put(Key(kMaxKey + i), rnd.RandomString(102)));
   }
   Flush();
   dbfull()->TEST_WaitForCompact();
diff --git a/db/db_range_del_test.cc b/db/db_range_del_test.cc
index b6f721b71..ca4a6f9fc 100644
--- a/db/db_range_del_test.cc
+++ b/db/db_range_del_test.cc
@@ -7,6 +7,7 @@
 #include "port/stack_trace.h"
 #include "rocksdb/utilities/write_batch_with_index.h"
 #include "test_util/testutil.h"
+#include "util/random.h"
 #include "utilities/merge_operators.h"
 
 namespace ROCKSDB_NAMESPACE {
@@ -124,7 +125,7 @@ TEST_F(DBRangeDelTest, CompactionOutputFilesExactlyFilled) {
     std::vector<std::string> values;
     // Write 12K (4 values, each 3K)
     for (int j = 0; j < kNumPerFile; j++) {
-      values.push_back(RandomString(&rnd, 3 << 10));
+      values.push_back(rnd.RandomString(3 << 10));
       ASSERT_OK(Put(Key(i * kNumPerFile + j), values[j]));
       if (j == 0 && i > 0) {
         dbfull()->TEST_WaitForFlushMemTable();
@@ -172,7 +173,7 @@ TEST_F(DBRangeDelTest, MaxCompactionBytesCutsOutputFiles) {
     std::vector<std::string> values;
     // Write 1MB (256 values, each 4K)
     for (int j = 0; j < kNumPerFile; j++) {
-      values.push_back(RandomString(&rnd, kBytesPerVal));
+      values.push_back(rnd.RandomString(kBytesPerVal));
       ASSERT_OK(Put(GetNumericStr(kNumPerFile * i + j), values[j]));
     }
     // extra entry to trigger SpecialSkipListFactory's flush
@@ -378,7 +379,7 @@ TEST_F(DBRangeDelTest, ValidLevelSubcompactionBoundaries) {
       std::vector<std::string> values;
       // Write 100KB (100 values, each 1K)
       for (int k = 0; k < kNumPerFile; k++) {
-        values.push_back(RandomString(&rnd, 990));
+        values.push_back(rnd.RandomString(990));
         ASSERT_OK(Put(Key(j * kNumPerFile + k), values[k]));
       }
       // put extra key to trigger flush
@@ -438,7 +439,7 @@ TEST_F(DBRangeDelTest, ValidUniversalSubcompactionBoundaries) {
       std::vector<std::string> values;
       // Write 100KB (100 values, each 1K)
       for (int k = 0; k < kNumPerFile; k++) {
-        values.push_back(RandomString(&rnd, 990));
+        values.push_back(rnd.RandomString(990));
         ASSERT_OK(Put(Key(j * kNumPerFile + k), values[k]));
       }
       // put extra key to trigger flush
@@ -990,7 +991,7 @@ TEST_F(DBRangeDelTest, CompactionTreatsSplitInputLevelDeletionAtomically) {
                      Key(2 * kNumFilesPerLevel));
 
     Random rnd(301);
-    std::string value = RandomString(&rnd, kValueBytes);
+    std::string value = rnd.RandomString(kValueBytes);
     for (int j = 0; j < kNumFilesPerLevel; ++j) {
       // give files overlapping key-ranges to prevent trivial move
       ASSERT_OK(Put(Key(j), value));
@@ -1063,7 +1064,7 @@ TEST_F(DBRangeDelTest, RangeTombstoneEndKeyAsSstableUpperBound) {
   //   [key000000#3,1, key000004#72057594037927935,15]
   //   [key000001#5,1, key000002#6,1]
   Random rnd(301);
-  std::string value = RandomString(&rnd, kValueBytes);
+  std::string value = rnd.RandomString(kValueBytes);
   for (int j = 0; j < kNumFilesPerLevel; ++j) {
     // Give files overlapping key-ranges to prevent a trivial move when we
     // compact from L0 to L1.
@@ -1198,7 +1199,7 @@ TEST_F(DBRangeDelTest, KeyAtOverlappingEndpointReappears) {
   const Snapshot* snapshot = nullptr;
   for (int i = 0; i < kNumFiles; ++i) {
     for (int j = 0; j < kFileBytes / kValueBytes; ++j) {
-      auto value = RandomString(&rnd, kValueBytes);
+      auto value = rnd.RandomString(kValueBytes);
       ASSERT_OK(db_->Merge(WriteOptions(), "key", value));
     }
     if (i == kNumFiles - 1) {
@@ -1282,7 +1283,7 @@ TEST_F(DBRangeDelTest, UntruncatedTombstoneDoesNotDeleteNewerKey) {
   const Snapshot* snapshots[] = {nullptr, nullptr};
   for (int i = 0; i < kNumFiles; ++i) {
     for (int j = 0; j < kFileBytes / kValueBytes; ++j) {
-      auto value = RandomString(&rnd, kValueBytes);
+      auto value = rnd.RandomString(kValueBytes);
       std::string key;
       if (i < kNumFiles / 2) {
         key = Key(0);
@@ -1328,7 +1329,7 @@ TEST_F(DBRangeDelTest, UntruncatedTombstoneDoesNotDeleteNewerKey) {
   // Now overwrite a few keys that are in L1 files that definitely don't have
   // overlapping boundary keys.
   for (int i = kMaxKey; i > kMaxKey - kKeysOverwritten; --i) {
-    auto value = RandomString(&rnd, kValueBytes);
+    auto value = rnd.RandomString(kValueBytes);
     ASSERT_OK(db_->Merge(WriteOptions(), Key(i), value));
   }
   ASSERT_OK(db_->Flush(FlushOptions()));
@@ -1375,7 +1376,7 @@ TEST_F(DBRangeDelTest, DeletedMergeOperandReappearsIterPrev) {
   const Snapshot* snapshot = nullptr;
   for (int i = 0; i < kNumFiles; ++i) {
     for (int j = 0; j < kFileBytes / kValueBytes; ++j) {
-      auto value = RandomString(&rnd, kValueBytes);
+      auto value = rnd.RandomString(kValueBytes);
       ASSERT_OK(db_->Merge(WriteOptions(), Key(j % kNumKeys), value));
       if (i == 0 && j == kNumKeys) {
         // Take snapshot to prevent covered merge operands from being dropped or
@@ -1515,7 +1516,7 @@ TEST_F(DBRangeDelTest, RangeTombstoneWrittenToMinimalSsts) {
     for (int i = 0; i < kFileBytes / kValueBytes; ++i) {
       std::string key(1, first_char);
       key.append(Key(i));
-      std::string value = RandomString(&rnd, kValueBytes);
+      std::string value = rnd.RandomString(kValueBytes);
       ASSERT_OK(Put(key, value));
     }
     db_->Flush(FlushOptions());
@@ -1597,7 +1598,7 @@ TEST_F(DBRangeDelTest, OverlappedTombstones) {
     std::vector<std::string> values;
     // Write 12K (4 values, each 3K)
     for (int j = 0; j < kNumPerFile; j++) {
-      values.push_back(RandomString(&rnd, 3 << 10));
+      values.push_back(rnd.RandomString(3 << 10));
       ASSERT_OK(Put(Key(i * kNumPerFile + j), values[j]));
     }
   }
@@ -1636,7 +1637,7 @@ TEST_F(DBRangeDelTest, OverlappedKeys) {
     std::vector<std::string> values;
     // Write 12K (4 values, each 3K)
     for (int j = 0; j < kNumPerFile; j++) {
-      values.push_back(RandomString(&rnd, 3 << 10));
+      values.push_back(rnd.RandomString(3 << 10));
       ASSERT_OK(Put(Key(i * kNumPerFile + j), values[j]));
     }
   }
diff --git a/db/db_sst_test.cc b/db/db_sst_test.cc
index 687d3b852..44e2380dc 100644
--- a/db/db_sst_test.cc
+++ b/db/db_sst_test.cc
@@ -12,6 +12,7 @@
 #include "port/port.h"
 #include "port/stack_trace.h"
 #include "rocksdb/sst_file_manager.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -163,7 +164,7 @@ TEST_F(DBSSTTest, DontDeleteMovedFile) {
   for (int i = 0; i < 2; ++i) {
     // Create 1MB sst file
     for (int j = 0; j < 100; ++j) {
-      ASSERT_OK(Put(Key(i * 50 + j), RandomString(&rnd, 10 * 1024)));
+      ASSERT_OK(Put(Key(i * 50 + j), rnd.RandomString(10 * 1024)));
     }
     ASSERT_OK(Flush());
   }
@@ -211,7 +212,7 @@ TEST_F(DBSSTTest, DeleteObsoleteFilesPendingOutputs) {
   for (int i = 0; i < 2; ++i) {
     // Create 1MB sst file
     for (int j = 0; j < 100; ++j) {
-      ASSERT_OK(Put(Key(i * 50 + j), RandomString(&rnd, 10 * 1024)));
+      ASSERT_OK(Put(Key(i * 50 + j), rnd.RandomString(10 * 1024)));
     }
     ASSERT_OK(Flush());
   }
@@ -242,7 +243,7 @@ TEST_F(DBSSTTest, DeleteObsoleteFilesPendingOutputs) {
   // write_buffer_size. The flush will be blocked with block_first_time
   // pending_file is protecting all the files created after
   for (int j = 0; j < 256; ++j) {
-    ASSERT_OK(Put(Key(j), RandomString(&rnd, 10 * 1024)));
+    ASSERT_OK(Put(Key(j), rnd.RandomString(10 * 1024)));
   }
   blocking_thread.WaitUntilSleeping();
 
@@ -758,7 +759,7 @@ TEST_F(DBSSTTest, DBWithMaxSpaceAllowed) {
 
   // Generate a file containing 100 keys.
   for (int i = 0; i < 100; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 50)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(50)));
   }
   ASSERT_OK(Flush());
 
@@ -799,7 +800,7 @@ TEST_F(DBSSTTest, CancellingCompactionsWorks) {
 
   // Generate a file containing 10 keys.
   for (int i = 0; i < 10; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 50)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(50)));
   }
   ASSERT_OK(Flush());
   uint64_t total_file_size = 0;
@@ -809,7 +810,7 @@ TEST_F(DBSSTTest, CancellingCompactionsWorks) {
 
   // Generate another file to trigger compaction.
   for (int i = 0; i < 10; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 50)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(50)));
   }
   ASSERT_OK(Flush());
   dbfull()->TEST_WaitForCompact(true);
@@ -846,7 +847,7 @@ TEST_F(DBSSTTest, CancellingManualCompactionsWorks) {
 
   // Generate a file containing 10 keys.
   for (int i = 0; i < 10; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 50)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(50)));
   }
   ASSERT_OK(Flush());
   uint64_t total_file_size = 0;
@@ -856,7 +857,7 @@ TEST_F(DBSSTTest, CancellingManualCompactionsWorks) {
 
   // Generate another file to trigger compaction.
   for (int i = 0; i < 10; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 50)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(50)));
   }
   ASSERT_OK(Flush());
 
@@ -953,7 +954,7 @@ TEST_F(DBSSTTest, DBWithMaxSpaceAllowedRandomized) {
     // It is easy to detect if the test is stuck in a loop. No need for
     // complex termination logic.
     while (true) {
-      auto s = Put(RandomString(&rnd, 10), RandomString(&rnd, 50));
+      auto s = Put(rnd.RandomString(10), rnd.RandomString(50));
       if (!s.ok()) {
         break;
       }
diff --git a/db/db_statistics_test.cc b/db/db_statistics_test.cc
index 8fbbb96d5..2450b1a53 100644
--- a/db/db_statistics_test.cc
+++ b/db/db_statistics_test.cc
@@ -9,6 +9,7 @@
 #include "monitoring/thread_status_util.h"
 #include "port/stack_trace.h"
 #include "rocksdb/statistics.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -55,7 +56,7 @@ TEST_F(DBStatisticsTest, CompressionStatsTest) {
   Random rnd(301);
   for (int i = 0; i < kNumKeysWritten; ++i) {
     // compressible string
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 128) + std::string(128, 'a')));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(128) + std::string(128, 'a')));
   }
   ASSERT_OK(Flush());
   ASSERT_GT(options.statistics->getTickerCount(NUMBER_BLOCK_COMPRESSED), 0);
@@ -75,7 +76,7 @@ TEST_F(DBStatisticsTest, CompressionStatsTest) {
   // Check that compressions do not occur when turned off
   for (int i = 0; i < kNumKeysWritten; ++i) {
     // compressible string
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 128) + std::string(128, 'a')));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(128) + std::string(128, 'a')));
   }
   ASSERT_OK(Flush());
   ASSERT_EQ(options.statistics->getTickerCount(NUMBER_BLOCK_COMPRESSED)
diff --git a/db/db_table_properties_test.cc b/db/db_table_properties_test.cc
index 98512e22f..cf71cc94a 100644
--- a/db/db_table_properties_test.cc
+++ b/db/db_table_properties_test.cc
@@ -16,6 +16,7 @@
 #include "rocksdb/utilities/table_properties_collectors.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
+#include "util/random.h"
 
 #ifndef ROCKSDB_LITE
 
@@ -155,12 +156,12 @@ TEST_F(DBTablePropertiesTest, GetPropertiesOfTablesInRange) {
 
   // build a decent LSM
   for (int i = 0; i < 10000; i++) {
-    ASSERT_OK(Put(test::RandomKey(&rnd, 5), RandomString(&rnd, 102)));
+    ASSERT_OK(Put(test::RandomKey(&rnd, 5), rnd.RandomString(102)));
   }
   Flush();
   dbfull()->TEST_WaitForCompact();
   if (NumTableFilesAtLevel(0) == 0) {
-    ASSERT_OK(Put(test::RandomKey(&rnd, 5), RandomString(&rnd, 102)));
+    ASSERT_OK(Put(test::RandomKey(&rnd, 5), rnd.RandomString(102)));
     Flush();
   }
 
diff --git a/db/db_test.cc b/db/db_test.cc
index 4fecae582..00668cc06 100644
--- a/db/db_test.cc
+++ b/db/db_test.cc
@@ -64,6 +64,7 @@
 #include "test_util/testutil.h"
 #include "util/compression.h"
 #include "util/mutexlock.h"
+#include "util/random.h"
 #include "util/rate_limiter.h"
 #include "util/string_util.h"
 #include "utilities/merge_operators.h"
@@ -914,7 +915,7 @@ TEST_F(DBTest, FlushSchedule) {
     WriteOptions wo;
     // this should fill up 2 memtables
     for (int k = 0; k < 5000; ++k) {
-      ASSERT_OK(db_->Put(wo, handles_[a & 1], RandomString(&rnd, 13), ""));
+      ASSERT_OK(db_->Put(wo, handles_[a & 1], rnd.RandomString(13), ""));
     }
   };
 
@@ -1171,7 +1172,7 @@ void MinLevelHelper(DBTest* self, Options& options) {
     std::vector<std::string> values;
     // Write 120KB (12 values, each 10K)
     for (int i = 0; i < 12; i++) {
-      values.push_back(DBTestBase::RandomString(&rnd, 10000));
+      values.push_back(rnd.RandomString(10000));
       ASSERT_OK(self->Put(DBTestBase::Key(i), values[i]));
     }
     self->dbfull()->TEST_WaitForFlushMemTable();
@@ -1181,7 +1182,7 @@ void MinLevelHelper(DBTest* self, Options& options) {
   // generate one more file in level-0, and should trigger level-0 compaction
   std::vector<std::string> values;
   for (int i = 0; i < 12; i++) {
-    values.push_back(DBTestBase::RandomString(&rnd, 10000));
+    values.push_back(rnd.RandomString(10000));
     ASSERT_OK(self->Put(DBTestBase::Key(i), values[i]));
   }
   self->dbfull()->TEST_WaitForCompact();
@@ -1294,7 +1295,7 @@ TEST_F(DBTest, DISABLED_RepeatedWritesToSameKey) {
 
     Random rnd(301);
     std::string value =
-        RandomString(&rnd, static_cast<int>(2 * options.write_buffer_size));
+        rnd.RandomString(static_cast<int>(2 * options.write_buffer_size));
     for (int i = 0; i < 5 * kMaxFiles; i++) {
       ASSERT_OK(Put(1, "key", value));
       ASSERT_LE(TotalTableFiles(1), kMaxFiles);
@@ -1370,7 +1371,7 @@ TEST_F(DBTest, ApproximateSizesMemTable) {
   const int N = 128;
   Random rnd(301);
   for (int i = 0; i < N; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 1024)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(1024)));
   }
 
   uint64_t size;
@@ -1394,7 +1395,7 @@ TEST_F(DBTest, ApproximateSizesMemTable) {
   ASSERT_EQ(size, 0);
 
   for (int i = 0; i < N; i++) {
-    ASSERT_OK(Put(Key(1000 + i), RandomString(&rnd, 1024)));
+    ASSERT_OK(Put(Key(1000 + i), rnd.RandomString(1024)));
   }
 
   start = Key(500);
@@ -1426,7 +1427,7 @@ TEST_F(DBTest, ApproximateSizesMemTable) {
   RandomShuffle(std::begin(keys), std::end(keys), rnd.Next());
 
   for (int i = 0; i < N * 3; i++) {
-    ASSERT_OK(Put(Key(keys[i] + 1000), RandomString(&rnd, 1024)));
+    ASSERT_OK(Put(Key(keys[i] + 1000), rnd.RandomString(1024)));
   }
 
   start = Key(100);
@@ -1460,7 +1461,7 @@ TEST_F(DBTest, ApproximateSizesMemTable) {
   Flush();
 
   for (int i = 0; i < N; i++) {
-    ASSERT_OK(Put(Key(i + 1000), RandomString(&rnd, 1024)));
+    ASSERT_OK(Put(Key(i + 1000), rnd.RandomString(1024)));
   }
 
   start = Key(1050);
@@ -1508,7 +1509,7 @@ TEST_F(DBTest, ApproximateSizesFilesWithErrorMargin) {
   const int N = 64000;
   Random rnd(301);
   for (int i = 0; i < N; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 24)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(24)));
   }
   // Flush everything to files
   Flush();
@@ -1517,7 +1518,7 @@ TEST_F(DBTest, ApproximateSizesFilesWithErrorMargin) {
 
   // Write more keys
   for (int i = N; i < (N + N / 4); i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 24)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(24)));
   }
   // Flush everything to files again
   Flush();
@@ -1576,7 +1577,7 @@ TEST_F(DBTest, GetApproximateMemTableStats) {
   const int N = 128;
   Random rnd(301);
   for (int i = 0; i < N; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 1024)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(1024)));
   }
 
   uint64_t count;
@@ -1608,7 +1609,7 @@ TEST_F(DBTest, GetApproximateMemTableStats) {
   ASSERT_EQ(size, 0);
 
   for (int i = 0; i < N; i++) {
-    ASSERT_OK(Put(Key(1000 + i), RandomString(&rnd, 1024)));
+    ASSERT_OK(Put(Key(1000 + i), rnd.RandomString(1024)));
   }
 
   start = Key(100);
@@ -1639,7 +1640,7 @@ TEST_F(DBTest, ApproximateSizes) {
     static const int S2 = 105000;  // Allow some expansion from metadata
     Random rnd(301);
     for (int i = 0; i < N; i++) {
-      ASSERT_OK(Put(1, Key(i), RandomString(&rnd, S1)));
+      ASSERT_OK(Put(1, Key(i), rnd.RandomString(S1)));
     }
 
     // 0 because GetApproximateSizes() does not account for memtable space
@@ -1682,15 +1683,15 @@ TEST_F(DBTest, ApproximateSizes_MixOfSmallAndLarge) {
     CreateAndReopenWithCF({"pikachu"}, options);
 
     Random rnd(301);
-    std::string big1 = RandomString(&rnd, 100000);
-    ASSERT_OK(Put(1, Key(0), RandomString(&rnd, 10000)));
-    ASSERT_OK(Put(1, Key(1), RandomString(&rnd, 10000)));
+    std::string big1 = rnd.RandomString(100000);
+    ASSERT_OK(Put(1, Key(0), rnd.RandomString(10000)));
+    ASSERT_OK(Put(1, Key(1), rnd.RandomString(10000)));
     ASSERT_OK(Put(1, Key(2), big1));
-    ASSERT_OK(Put(1, Key(3), RandomString(&rnd, 10000)));
+    ASSERT_OK(Put(1, Key(3), rnd.RandomString(10000)));
     ASSERT_OK(Put(1, Key(4), big1));
-    ASSERT_OK(Put(1, Key(5), RandomString(&rnd, 10000)));
-    ASSERT_OK(Put(1, Key(6), RandomString(&rnd, 300000)));
-    ASSERT_OK(Put(1, Key(7), RandomString(&rnd, 10000)));
+    ASSERT_OK(Put(1, Key(5), rnd.RandomString(10000)));
+    ASSERT_OK(Put(1, Key(6), rnd.RandomString(300000)));
+    ASSERT_OK(Put(1, Key(7), rnd.RandomString(10000)));
 
     // Check sizes across recovery by reopening a few times
     for (int run = 0; run < 3; run++) {
@@ -1797,7 +1798,7 @@ TEST_F(DBTest, HiddenValuesAreRemoved) {
     Random rnd(301);
     FillLevels("a", "z", 1);
 
-    std::string big = RandomString(&rnd, 50000);
+    std::string big = rnd.RandomString(50000);
     Put(1, "foo", big);
     Put(1, "pastfoo", "v");
     const Snapshot* snapshot = db_->GetSnapshot();
@@ -2187,7 +2188,7 @@ TEST_F(DBTest, SnapshotFiles) {
     ASSERT_EQ(NumTableFilesAtLevel(0, 1), 0);
     std::vector<std::string> values;
     for (int i = 0; i < 80; i++) {
-      values.push_back(RandomString(&rnd, 100000));
+      values.push_back(rnd.RandomString(100000));
       ASSERT_OK(Put((i < 40), Key(i), values[i]));
     }
 
@@ -2240,7 +2241,7 @@ TEST_F(DBTest, SnapshotFiles) {
     // overwrite one key, this key should not appear in the snapshot
     std::vector<std::string> extras;
     for (unsigned int i = 0; i < 1; i++) {
-      extras.push_back(RandomString(&rnd, 100000));
+      extras.push_back(rnd.RandomString(100000));
       ASSERT_OK(Put(0, Key(i), extras[i]));
     }
 
@@ -3206,8 +3207,8 @@ TEST_P(DBTestRandomized, Randomized) {
     }
     if (p < 45) {  // Put
       k = RandomKey(&rnd, minimum);
-      v = RandomString(&rnd,
-                       rnd.OneIn(20) ? 100 + rnd.Uniform(100) : rnd.Uniform(8));
+      v = rnd.RandomString(rnd.OneIn(20) ? 100 + rnd.Uniform(100)
+                                         : rnd.Uniform(8));
       ASSERT_OK(model.Put(WriteOptions(), k, v));
       ASSERT_OK(db_->Put(WriteOptions(), k, v));
     } else if (p < 90) {  // Delete
@@ -3225,7 +3226,7 @@ TEST_P(DBTestRandomized, Randomized) {
           // we have multiple entries in the write batch for the same key
         }
         if (rnd.OneIn(2)) {
-          v = RandomString(&rnd, rnd.Uniform(10));
+          v = rnd.RandomString(rnd.Uniform(10));
           b.Put(k, v);
         } else {
           b.Delete(k);
@@ -3395,7 +3396,7 @@ TEST_P(DBTestWithParam, FIFOCompactionTest) {
     Random rnd(301);
     for (int i = 0; i < 6; ++i) {
       for (int j = 0; j < 110; ++j) {
-        ASSERT_OK(Put(ToString(i * 100 + j), RandomString(&rnd, 980)));
+        ASSERT_OK(Put(ToString(i * 100 + j), rnd.RandomString(980)));
       }
       // flush should happen here
       ASSERT_OK(dbfull()->TEST_WaitForFlushMemTable());
@@ -3433,7 +3434,7 @@ TEST_F(DBTest, FIFOCompactionTestWithCompaction) {
   for (int i = 0; i < 60; i++) {
     // Generate and flush a file about 20KB.
     for (int j = 0; j < 20; j++) {
-      ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+      ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
     }
     Flush();
     ASSERT_OK(dbfull()->TEST_WaitForCompact());
@@ -3444,7 +3445,7 @@ TEST_F(DBTest, FIFOCompactionTestWithCompaction) {
   for (int i = 0; i < 60; i++) {
     // Generate and flush a file about 20KB.
     for (int j = 0; j < 20; j++) {
-      ASSERT_OK(Put(ToString(i * 20 + j + 2000), RandomString(&rnd, 980)));
+      ASSERT_OK(Put(ToString(i * 20 + j + 2000), rnd.RandomString(980)));
     }
     Flush();
     ASSERT_OK(dbfull()->TEST_WaitForCompact());
@@ -3474,9 +3475,9 @@ TEST_F(DBTest, FIFOCompactionStyleWithCompactionAndDelete) {
   Random rnd(301);
   for (int i = 0; i < 3; i++) {
     // Each file contains a different key which will be dropped later.
-    ASSERT_OK(Put("a" + ToString(i), RandomString(&rnd, 500)));
+    ASSERT_OK(Put("a" + ToString(i), rnd.RandomString(500)));
     ASSERT_OK(Put("key" + ToString(i), ""));
-    ASSERT_OK(Put("z" + ToString(i), RandomString(&rnd, 500)));
+    ASSERT_OK(Put("z" + ToString(i), rnd.RandomString(500)));
     Flush();
     ASSERT_OK(dbfull()->TEST_WaitForCompact());
   }
@@ -3486,9 +3487,9 @@ TEST_F(DBTest, FIFOCompactionStyleWithCompactionAndDelete) {
   }
   for (int i = 0; i < 3; i++) {
     // Each file contains a different key which will be dropped later.
-    ASSERT_OK(Put("a" + ToString(i), RandomString(&rnd, 500)));
+    ASSERT_OK(Put("a" + ToString(i), rnd.RandomString(500)));
     ASSERT_OK(Delete("key" + ToString(i)));
-    ASSERT_OK(Put("z" + ToString(i), RandomString(&rnd, 500)));
+    ASSERT_OK(Put("z" + ToString(i), rnd.RandomString(500)));
     Flush();
     ASSERT_OK(dbfull()->TEST_WaitForCompact());
   }
@@ -3558,7 +3559,7 @@ TEST_F(DBTest, FIFOCompactionWithTTLTest) {
     for (int i = 0; i < 10; i++) {
       // Generate and flush a file about 10KB.
       for (int j = 0; j < 10; j++) {
-        ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+        ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
       }
       Flush();
       ASSERT_OK(dbfull()->TEST_WaitForCompact());
@@ -3593,7 +3594,7 @@ TEST_F(DBTest, FIFOCompactionWithTTLTest) {
     for (int i = 0; i < 10; i++) {
       // Generate and flush a file about 10KB.
       for (int j = 0; j < 10; j++) {
-        ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+        ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
       }
       Flush();
       ASSERT_OK(dbfull()->TEST_WaitForCompact());
@@ -3609,7 +3610,7 @@ TEST_F(DBTest, FIFOCompactionWithTTLTest) {
     // Create 1 more file to trigger TTL compaction. The old files are dropped.
     for (int i = 0; i < 1; i++) {
       for (int j = 0; j < 10; j++) {
-        ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+        ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
       }
       Flush();
     }
@@ -3635,7 +3636,7 @@ TEST_F(DBTest, FIFOCompactionWithTTLTest) {
     for (int i = 0; i < 3; i++) {
       // Generate and flush a file about 10KB.
       for (int j = 0; j < 10; j++) {
-        ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+        ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
       }
       Flush();
       ASSERT_OK(dbfull()->TEST_WaitForCompact());
@@ -3650,7 +3651,7 @@ TEST_F(DBTest, FIFOCompactionWithTTLTest) {
 
     for (int i = 0; i < 5; i++) {
       for (int j = 0; j < 140; j++) {
-        ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+        ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
       }
       Flush();
       ASSERT_OK(dbfull()->TEST_WaitForCompact());
@@ -3673,7 +3674,7 @@ TEST_F(DBTest, FIFOCompactionWithTTLTest) {
     for (int i = 0; i < 10; i++) {
       // Generate and flush a file about 10KB.
       for (int j = 0; j < 10; j++) {
-        ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+        ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
       }
       Flush();
       ASSERT_OK(dbfull()->TEST_WaitForCompact());
@@ -3692,7 +3693,7 @@ TEST_F(DBTest, FIFOCompactionWithTTLTest) {
     // Create 10 more files. The old 5 files are dropped as their ttl expired.
     for (int i = 0; i < 10; i++) {
       for (int j = 0; j < 10; j++) {
-        ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+        ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
       }
       Flush();
       ASSERT_OK(dbfull()->TEST_WaitForCompact());
@@ -3717,7 +3718,7 @@ TEST_F(DBTest, FIFOCompactionWithTTLTest) {
     for (int i = 0; i < 60; i++) {
       // Generate and flush a file about 20KB.
       for (int j = 0; j < 20; j++) {
-        ASSERT_OK(Put(ToString(i * 20 + j), RandomString(&rnd, 980)));
+        ASSERT_OK(Put(ToString(i * 20 + j), rnd.RandomString(980)));
       }
       Flush();
       ASSERT_OK(dbfull()->TEST_WaitForCompact());
@@ -3728,7 +3729,7 @@ TEST_F(DBTest, FIFOCompactionWithTTLTest) {
     for (int i = 0; i < 60; i++) {
       // Generate and flush a file about 20KB.
       for (int j = 0; j < 20; j++) {
-        ASSERT_OK(Put(ToString(i * 20 + j + 2000), RandomString(&rnd, 980)));
+        ASSERT_OK(Put(ToString(i * 20 + j + 2000), rnd.RandomString(980)));
       }
       Flush();
       ASSERT_OK(dbfull()->TEST_WaitForCompact());
@@ -3771,8 +3772,7 @@ TEST_F(DBTest, DISABLED_RateLimitingTest) {
   uint64_t start = env_->NowMicros();
   // Write ~96M data
   for (int64_t i = 0; i < (96 << 10); ++i) {
-    ASSERT_OK(
-        Put(RandomString(&rnd, 32), RandomString(&rnd, (1 << 10) + 1), wo));
+    ASSERT_OK(Put(rnd.RandomString(32), rnd.RandomString((1 << 10) + 1), wo));
   }
   uint64_t elapsed = env_->NowMicros() - start;
   double raw_rate = env_->bytes_written_ * 1000000.0 / elapsed;
@@ -3790,8 +3790,7 @@ TEST_F(DBTest, DISABLED_RateLimitingTest) {
   start = env_->NowMicros();
   // Write ~96M data
   for (int64_t i = 0; i < (96 << 10); ++i) {
-    ASSERT_OK(
-        Put(RandomString(&rnd, 32), RandomString(&rnd, (1 << 10) + 1), wo));
+    ASSERT_OK(Put(rnd.RandomString(32), rnd.RandomString((1 << 10) + 1), wo));
   }
   rate_limiter_drains =
       TestGetTickerCount(options, NUMBER_RATE_LIMITER_DRAINS) -
@@ -3816,8 +3815,7 @@ TEST_F(DBTest, DISABLED_RateLimitingTest) {
   start = env_->NowMicros();
   // Write ~96M data
   for (int64_t i = 0; i < (96 << 10); ++i) {
-    ASSERT_OK(
-        Put(RandomString(&rnd, 32), RandomString(&rnd, (1 << 10) + 1), wo));
+    ASSERT_OK(Put(rnd.RandomString(32), rnd.RandomString((1 << 10) + 1), wo));
   }
   elapsed = env_->NowMicros() - start;
   rate_limiter_drains =
@@ -4018,7 +4016,7 @@ TEST_F(DBTest, DynamicMemtableOptions) {
     const int kNumPutsBeforeWaitForFlush = 64;
     Random rnd(301);
     for (int i = 0; i < size; i++) {
-      ASSERT_OK(Put(Key(i), RandomString(&rnd, 1024)));
+      ASSERT_OK(Put(Key(i), rnd.RandomString(1024)));
 
       // The following condition prevents a race condition between flush jobs
       // acquiring work and this thread filling up multiple memtables. Without
@@ -4092,7 +4090,7 @@ TEST_F(DBTest, DynamicMemtableOptions) {
   ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
 
   while (!sleeping_task_low.WokenUp() && count < 256) {
-    ASSERT_OK(Put(Key(count), RandomString(&rnd, 1024), WriteOptions()));
+    ASSERT_OK(Put(Key(count), rnd.RandomString(1024), WriteOptions()));
     count++;
   }
   ASSERT_GT(static_cast<double>(count), 128 * 0.8);
@@ -4112,7 +4110,7 @@ TEST_F(DBTest, DynamicMemtableOptions) {
                  Env::Priority::LOW);
   count = 0;
   while (!sleeping_task_low.WokenUp() && count < 1024) {
-    ASSERT_OK(Put(Key(count), RandomString(&rnd, 1024), WriteOptions()));
+    ASSERT_OK(Put(Key(count), rnd.RandomString(1024), WriteOptions()));
     count++;
   }
 // Windows fails this test. Will tune in the future and figure out
@@ -4136,7 +4134,7 @@ TEST_F(DBTest, DynamicMemtableOptions) {
 
   count = 0;
   while (!sleeping_task_low.WokenUp() && count < 1024) {
-    ASSERT_OK(Put(Key(count), RandomString(&rnd, 1024), WriteOptions()));
+    ASSERT_OK(Put(Key(count), rnd.RandomString(1024), WriteOptions()));
     count++;
   }
 // Windows fails this test. Will tune in the future and figure out
@@ -4323,7 +4321,7 @@ TEST_P(DBTestWithParam, ThreadStatusSingleCompaction) {
     for (int file = 0; file < kNumL0Files; ++file) {
       for (int key = 0; key < kEntriesPerBuffer; ++key) {
         ASSERT_OK(Put(ToString(key + file * kEntriesPerBuffer),
-                      RandomString(&rnd, kTestValueSize)));
+                      rnd.RandomString(kTestValueSize)));
       }
       Flush();
     }
@@ -4471,7 +4469,7 @@ TEST_P(DBTestWithParam, PreShutdownMultipleCompaction) {
   int operation_count[ThreadStatus::NUM_OP_TYPES] = {0};
   for (int file = 0; file < 16 * kNumL0Files; ++file) {
     for (int k = 0; k < kEntriesPerBuffer; ++k) {
-      ASSERT_OK(Put(ToString(key++), RandomString(&rnd, kTestValueSize)));
+      ASSERT_OK(Put(ToString(key++), rnd.RandomString(kTestValueSize)));
     }
 
     Status s = env_->GetThreadList(&thread_list);
@@ -4558,7 +4556,7 @@ TEST_P(DBTestWithParam, PreShutdownCompactionMiddle) {
   int operation_count[ThreadStatus::NUM_OP_TYPES] = {0};
   for (int file = 0; file < 16 * kNumL0Files; ++file) {
     for (int k = 0; k < kEntriesPerBuffer; ++k) {
-      ASSERT_OK(Put(ToString(key++), RandomString(&rnd, kTestValueSize)));
+      ASSERT_OK(Put(ToString(key++), rnd.RandomString(kTestValueSize)));
     }
 
     Status s = env_->GetThreadList(&thread_list);
@@ -4744,7 +4742,7 @@ TEST_F(DBTest, DynamicLevelCompressionPerLevel2) {
   ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
 
   for (int i = 0; i < 100; i++) {
-    std::string value = RandomString(&rnd, 200);
+    std::string value = rnd.RandomString(200);
     ASSERT_OK(Put(Key(keys[i]), value));
     if (i % 25 == 24) {
       Flush();
@@ -4789,7 +4787,7 @@ TEST_F(DBTest, DynamicLevelCompressionPerLevel2) {
   ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
 
   for (int i = 101; i < 500; i++) {
-    std::string value = RandomString(&rnd, 200);
+    std::string value = rnd.RandomString(200);
     ASSERT_OK(Put(Key(keys[i]), value));
     if (i % 100 == 99) {
       Flush();
@@ -4841,7 +4839,7 @@ TEST_F(DBTest, DynamicCompactionOptions) {
   auto gen_l0_kb = [this](int start, int size, int stride) {
     Random rnd(301);
     for (int i = 0; i < size; i++) {
-      ASSERT_OK(Put(Key(start + stride * i), RandomString(&rnd, 1024)));
+      ASSERT_OK(Put(Key(start + stride * i), rnd.RandomString(1024)));
     }
     dbfull()->TEST_WaitForFlushMemTable();
   };
@@ -4936,7 +4934,7 @@ TEST_F(DBTest, DynamicCompactionOptions) {
   Random rnd(301);
   WriteOptions wo;
   while (count < 64) {
-    ASSERT_OK(Put(Key(count), RandomString(&rnd, 1024), wo));
+    ASSERT_OK(Put(Key(count), rnd.RandomString(1024), wo));
     dbfull()->TEST_FlushMemTable(true, true);
     count++;
     if (dbfull()->TEST_write_controler().IsStopped()) {
@@ -4964,7 +4962,7 @@ TEST_F(DBTest, DynamicCompactionOptions) {
   sleeping_task_low.WaitUntilSleeping();
   count = 0;
   while (count < 64) {
-    ASSERT_OK(Put(Key(count), RandomString(&rnd, 1024), wo));
+    ASSERT_OK(Put(Key(count), rnd.RandomString(1024), wo));
     dbfull()->TEST_FlushMemTable(true, true);
     count++;
     if (dbfull()->TEST_write_controler().IsStopped()) {
@@ -4986,7 +4984,7 @@ TEST_F(DBTest, DynamicCompactionOptions) {
   ASSERT_EQ(NumTableFilesAtLevel(0), 0);
 
   for (int i = 0; i < 4; ++i) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 1024)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(1024)));
     // Wait for compaction so that put won't stop
     dbfull()->TEST_FlushMemTable(true);
   }
@@ -5000,7 +4998,7 @@ TEST_F(DBTest, DynamicCompactionOptions) {
   ASSERT_EQ(NumTableFilesAtLevel(0), 0);
 
   for (int i = 0; i < 4; ++i) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 1024)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(1024)));
     // Wait for compaction so that put won't stop
     dbfull()->TEST_FlushMemTable(true);
   }
@@ -5174,7 +5172,7 @@ TEST_F(DBTest, FileCreationRandomFailure) {
     }
     for (int k = 0; k < kTestSize; ++k) {
       // here we expect some of the Put fails.
-      std::string value = RandomString(&rnd, 100);
+      std::string value = rnd.RandomString(100);
       Status s = Put(Key(k), Slice(value));
       if (s.ok()) {
         // update the latest successful put
@@ -5223,11 +5221,11 @@ TEST_F(DBTest, DynamicMiscOptions) {
     int key1 = key_start + 1;
     int key2 = key_start + 2;
     Random rnd(301);
-    ASSERT_OK(Put(Key(key0), RandomString(&rnd, 8)));
+    ASSERT_OK(Put(Key(key0), rnd.RandomString(8)));
     for (int i = 0; i < 10; ++i) {
-      ASSERT_OK(Put(Key(key1), RandomString(&rnd, 8)));
+      ASSERT_OK(Put(Key(key1), rnd.RandomString(8)));
     }
-    ASSERT_OK(Put(Key(key2), RandomString(&rnd, 8)));
+    ASSERT_OK(Put(Key(key2), rnd.RandomString(8)));
     std::unique_ptr<Iterator> iter(db_->NewIterator(ReadOptions()));
     iter->Seek(Key(key1));
     ASSERT_TRUE(iter->Valid());
@@ -5367,7 +5365,7 @@ TEST_F(DBTest, EncodeDecompressedBlockSizeTest) {
       Random rnd(301);
       for (int i = 0; i < kNumKeysWritten; ++i) {
         // compressible string
-        ASSERT_OK(Put(Key(i), RandomString(&rnd, 128) + std::string(128, 'a')));
+        ASSERT_OK(Put(Key(i), rnd.RandomString(128) + std::string(128, 'a')));
       }
 
       table_options.format_version = first_table_version == 1 ? 2 : 1;
@@ -5712,7 +5710,7 @@ TEST_F(DBTest, PromoteL0) {
   std::map<int32_t, std::string> values;
   for (const auto& range : ranges) {
     for (int32_t j = range.first; j < range.second; j++) {
-      values[j] = RandomString(&rnd, value_size);
+      values[j] = rnd.RandomString(value_size);
       ASSERT_OK(Put(Key(j), values[j]));
     }
     ASSERT_OK(Flush());
@@ -5773,7 +5771,7 @@ TEST_F(DBTest, CompactRangeWithEmptyBottomLevel) {
 
   Random rnd(301);
   for (int i = 0; i < kNumL0Files; ++i) {
-    ASSERT_OK(Put(Key(0), RandomString(&rnd, 1024)));
+    ASSERT_OK(Put(Key(0), rnd.RandomString(1024)));
     Flush();
   }
   ASSERT_EQ(NumTableFilesAtLevel(0), kNumL0Files);
@@ -5812,7 +5810,7 @@ TEST_F(DBTest, AutomaticConflictsWithManualCompaction) {
   for (int i = 0; i < 2; ++i) {
     // put two keys to ensure no trivial move
     for (int j = 0; j < 2; ++j) {
-      ASSERT_OK(Put(Key(j), RandomString(&rnd, 1024)));
+      ASSERT_OK(Put(Key(j), rnd.RandomString(1024)));
     }
     ASSERT_OK(Flush());
   }
@@ -5826,7 +5824,7 @@ TEST_F(DBTest, AutomaticConflictsWithManualCompaction) {
   for (int i = 0; i < kNumL0Files; ++i) {
     // put two keys to ensure no trivial move
     for (int j = 0; j < 2; ++j) {
-      ASSERT_OK(Put(Key(j), RandomString(&rnd, 1024)));
+      ASSERT_OK(Put(Key(j), rnd.RandomString(1024)));
     }
     ASSERT_OK(Flush());
   }
@@ -5855,7 +5853,7 @@ TEST_F(DBTest, CompactFilesShouldTriggerAutoCompaction) {
   for (int i = 0; i < 2; ++i) {
     // put two keys to ensure no trivial move
     for (int j = 0; j < 2; ++j) {
-      ASSERT_OK(Put(Key(j), RandomString(&rnd, 1024)));
+      ASSERT_OK(Put(Key(j), rnd.RandomString(1024)));
     }
     ASSERT_OK(Flush());
   }
@@ -5885,7 +5883,7 @@ TEST_F(DBTest, CompactFilesShouldTriggerAutoCompaction) {
   // generate enough files to trigger compaction
   for (int i = 0; i < 20; ++i) {
     for (int j = 0; j < 2; ++j) {
-      ASSERT_OK(Put(Key(j), RandomString(&rnd, 1024)));
+      ASSERT_OK(Put(Key(j), rnd.RandomString(1024)));
     }
     ASSERT_OK(Flush());
   }
@@ -6496,7 +6494,7 @@ TEST_F(DBTest, PauseBackgroundWorkTest) {
   threads.emplace_back([&]() {
     Random rnd(301);
     for (int i = 0; i < 10000; ++i) {
-      Put(RandomString(&rnd, 10), RandomString(&rnd, 10));
+      Put(rnd.RandomString(10), rnd.RandomString(10));
     }
     done.store(true);
   });
@@ -6626,7 +6624,7 @@ TEST_F(DBTest, CreationTimeOfOldestFile) {
   for (int i = 0; i < kNumLevelFiles; ++i) {
     for (int j = 0; j < kNumKeysPerFile; ++j) {
       ASSERT_OK(
-          Put(Key(i * kNumKeysPerFile + j), RandomString(&rnd, kValueSize)));
+          Put(Key(i * kNumKeysPerFile + j), rnd.RandomString(kValueSize)));
     }
     Flush();
   }
@@ -6651,7 +6649,7 @@ TEST_F(DBTest, CreationTimeOfOldestFile) {
   for (int i = 0; i < kNumLevelFiles; ++i) {
     for (int j = 0; j < kNumKeysPerFile; ++j) {
       ASSERT_OK(
-          Put(Key(i * kNumKeysPerFile + j), RandomString(&rnd, kValueSize)));
+          Put(Key(i * kNumKeysPerFile + j), rnd.RandomString(kValueSize)));
     }
     Flush();
   }
diff --git a/db/db_test2.cc b/db/db_test2.cc
index 95a7f557a..b01d15dba 100644
--- a/db/db_test2.cc
+++ b/db/db_test2.cc
@@ -16,7 +16,8 @@
 #include "port/stack_trace.h"
 #include "rocksdb/persistent_cache.h"
 #include "rocksdb/wal_filter.h"
-#include "test_util/fault_injection_test_env.h"
+#include "util/random.h"
+#include "utilities/fault_injection_env.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -166,7 +167,7 @@ TEST_F(DBTest2, PartitionedIndexUserToInternalKey) {
 
   for (int i = 0; i < 3000; i++) {
     int j = i % 30;
-    std::string value = RandomString(&rnd, 10500);
+    std::string value = rnd.RandomString(10500);
     ASSERT_OK(Put("keykey_" + std::to_string(j), value));
     snapshots.push_back(db_->GetSnapshot());
   }
@@ -1274,7 +1275,7 @@ TEST_F(DBTest2, PresetCompressionDict) {
       std::string seq_datas[10];
       for (int j = 0; j < 10; ++j) {
         seq_datas[j] =
-            RandomString(&rnd, kBlockSizeBytes - kApproxPerBlockOverheadBytes);
+            rnd.RandomString(kBlockSizeBytes - kApproxPerBlockOverheadBytes);
       }
 
       ASSERT_EQ(0, NumTableFilesAtLevel(0, 1));
@@ -1349,7 +1350,7 @@ TEST_F(DBTest2, PresetCompressionDictLocality) {
   for (int i = 0; i < kNumFiles; ++i) {
     for (int j = 0; j < kNumEntriesPerFile; ++j) {
       ASSERT_OK(Put(Key(i * kNumEntriesPerFile + j),
-                    RandomString(&rnd, kNumBytesPerEntry)));
+                    rnd.RandomString(kNumBytesPerEntry)));
     }
     ASSERT_OK(Flush());
     MoveFilesToLevel(1);
@@ -1519,9 +1520,9 @@ TEST_P(CompressionFailuresTest, CompressionFailures) {
   // Write 10 random files
   for (int i = 0; i < 10; i++) {
     for (int j = 0; j < 5; j++) {
-      std::string key = RandomString(&rnd, kKeySize);
+      std::string key = rnd.RandomString(kKeySize);
       // Ensure good compression ratio
-      std::string valueUnit = RandomString(&rnd, kValUnitSize);
+      std::string valueUnit = rnd.RandomString(kValUnitSize);
       std::string value;
       for (int k = 0; k < kValSize; k += kValUnitSize) {
         value += valueUnit;
@@ -1623,8 +1624,8 @@ TEST_F(DBTest2, CompressionOptions) {
       // Write 10 random files
       for (int i = 0; i < 10; i++) {
         for (int j = 0; j < 5; j++) {
-          std::string key = RandomString(&rnd, kKeySize);
-          std::string value = RandomString(&rnd, kValSize);
+          std::string key = rnd.RandomString(kKeySize);
+          std::string value = rnd.RandomString(kValSize);
           key_value_written[key] = value;
           ASSERT_OK(Put(key, value));
         }
@@ -1696,7 +1697,7 @@ TEST_F(DBTest2, CompactionStall) {
   // 4 Files in L0
   for (int i = 0; i < 4; i++) {
     for (int j = 0; j < 10; j++) {
-      ASSERT_OK(Put(RandomString(&rnd, 10), RandomString(&rnd, 10)));
+      ASSERT_OK(Put(rnd.RandomString(10), rnd.RandomString(10)));
     }
     ASSERT_OK(Flush());
   }
@@ -1711,7 +1712,7 @@ TEST_F(DBTest2, CompactionStall) {
   // Another 6 L0 files to trigger compaction again
   for (int i = 0; i < 6; i++) {
     for (int j = 0; j < 10; j++) {
-      ASSERT_OK(Put(RandomString(&rnd, 10), RandomString(&rnd, 10)));
+      ASSERT_OK(Put(rnd.RandomString(10), rnd.RandomString(10)));
     }
     ASSERT_OK(Flush());
   }
@@ -2311,7 +2312,7 @@ TEST_F(DBTest2, PersistentCache) {
       std::string str;
       for (int i = 0; i < num_iter; i++) {
         if (i % 4 == 0) {  // high compression ratio
-          str = RandomString(&rnd, 1000);
+          str = rnd.RandomString(1000);
         }
         values.push_back(str);
         ASSERT_OK(Put(1, Key(i), values[i]));
@@ -2409,7 +2410,7 @@ TEST_F(DBTest2, ReadAmpBitmap) {
 
     Random rnd(301);
     for (size_t i = 0; i < kNumEntries; i++) {
-      ASSERT_OK(Put(Key(static_cast<int>(i)), RandomString(&rnd, 100)));
+      ASSERT_OK(Put(Key(static_cast<int>(i)), rnd.RandomString(100)));
     }
     ASSERT_OK(Flush());
 
@@ -2516,7 +2517,7 @@ TEST_F(DBTest2, ReadAmpBitmapLiveInCacheAfterDBClose) {
 
     Random rnd(301);
     for (int i = 0; i < kNumEntries; i++) {
-      ASSERT_OK(Put(Key(i), RandomString(&rnd, 100)));
+      ASSERT_OK(Put(Key(i), rnd.RandomString(100)));
     }
     ASSERT_OK(Flush());
 
@@ -2739,13 +2740,13 @@ TEST_F(DBTest2, PausingManualCompaction1) {
   Random rnd(301);
   // Generate a file containing 10 keys.
   for (int i = 0; i < 10; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 50)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(50)));
   }
   ASSERT_OK(Flush());
 
   // Generate another file containing same keys
   for (int i = 0; i < 10; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 50)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(50)));
   }
   ASSERT_OK(Flush());
 
@@ -2818,7 +2819,7 @@ TEST_F(DBTest2, PausingManualCompaction2) {
   for (int i = 0; i < 2; i++) {
     // Generate a file containing 10 keys.
     for (int j = 0; j < 100; j++) {
-      ASSERT_OK(Put(Key(j), RandomString(&rnd, 50)));
+      ASSERT_OK(Put(Key(j), rnd.RandomString(50)));
     }
     ASSERT_OK(Flush());
   }
@@ -2840,7 +2841,7 @@ TEST_F(DBTest2, PausingManualCompaction3) {
     for (int i = 0; i < options.num_levels; i++) {
       for (int j = 0; j < options.num_levels - i + 1; j++) {
         for (int k = 0; k < 1000; k++) {
-          ASSERT_OK(Put(Key(k + j * 1000), RandomString(&rnd, 50)));
+          ASSERT_OK(Put(Key(k + j * 1000), rnd.RandomString(50)));
         }
         Flush();
       }
@@ -2894,7 +2895,7 @@ TEST_F(DBTest2, PausingManualCompaction4) {
     for (int i = 0; i < options.num_levels; i++) {
       for (int j = 0; j < options.num_levels - i + 1; j++) {
         for (int k = 0; k < 1000; k++) {
-          ASSERT_OK(Put(Key(k + j * 1000), RandomString(&rnd, 50)));
+          ASSERT_OK(Put(Key(k + j * 1000), rnd.RandomString(50)));
         }
         Flush();
       }
@@ -4021,7 +4022,7 @@ TEST_F(DBTest2, DISABLED_IteratorPinnedMemory) {
   Reopen(options);
 
   Random rnd(301);
-  std::string v = RandomString(&rnd, 400);
+  std::string v = rnd.RandomString(400);
 
   // Since v is the size of a block, each key should take a block
   // of 400+ bytes.
@@ -4749,7 +4750,7 @@ TEST_F(DBTest2, BlockBasedTablePrefixIndexSeekForPrev) {
   Reopen(options);
 
   Random rnd(301);
-  std::string large_value = RandomString(&rnd, 500);
+  std::string large_value = rnd.RandomString(500);
 
   ASSERT_OK(Put("a1", large_value));
   ASSERT_OK(Put("x1", large_value));
@@ -5011,7 +5012,7 @@ TEST_F(DBTest2, AutoPrefixMode1) {
   Reopen(options);
 
   Random rnd(301);
-  std::string large_value = RandomString(&rnd, 500);
+  std::string large_value = rnd.RandomString(500);
 
   ASSERT_OK(Put("a1", large_value));
   ASSERT_OK(Put("x1", large_value));
diff --git a/db/db_test_util.cc b/db/db_test_util.cc
index c2c1d44ea..b40eac672 100644
--- a/db/db_test_util.cc
+++ b/db/db_test_util.cc
@@ -8,9 +8,11 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 
 #include "db/db_test_util.h"
+
 #include "db/forward_iterator.h"
 #include "rocksdb/env_encryption.h"
 #include "rocksdb/utilities/object_registry.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -408,7 +410,7 @@ Options DBTestBase::GetOptions(
         options.use_direct_reads = true;
         options.use_direct_io_for_flush_and_compaction = true;
         options.compaction_readahead_size = 2 * 1024 * 1024;
-        test::SetupSyncPointsToMockDirectIO();
+        SetupSyncPointsToMockDirectIO();
         break;
       }
 #endif  // ROCKSDB_LITE
@@ -1192,7 +1194,7 @@ int DBTestBase::GetSstFileCount(std::string path) {
 void DBTestBase::GenerateNewFile(int cf, Random* rnd, int* key_idx,
                                  bool nowait) {
   for (int i = 0; i < KNumKeysByGenerateNewFile; i++) {
-    ASSERT_OK(Put(cf, Key(*key_idx), RandomString(rnd, (i == 99) ? 1 : 990)));
+    ASSERT_OK(Put(cf, Key(*key_idx), rnd->RandomString((i == 99) ? 1 : 990)));
     (*key_idx)++;
   }
   if (!nowait) {
@@ -1204,7 +1206,7 @@ void DBTestBase::GenerateNewFile(int cf, Random* rnd, int* key_idx,
 // this will generate non-overlapping files since it keeps increasing key_idx
 void DBTestBase::GenerateNewFile(Random* rnd, int* key_idx, bool nowait) {
   for (int i = 0; i < KNumKeysByGenerateNewFile; i++) {
-    ASSERT_OK(Put(Key(*key_idx), RandomString(rnd, (i == 99) ? 1 : 990)));
+    ASSERT_OK(Put(Key(*key_idx), rnd->RandomString((i == 99) ? 1 : 990)));
     (*key_idx)++;
   }
   if (!nowait) {
@@ -1217,9 +1219,9 @@ const int DBTestBase::kNumKeysByGenerateNewRandomFile = 51;
 
 void DBTestBase::GenerateNewRandomFile(Random* rnd, bool nowait) {
   for (int i = 0; i < kNumKeysByGenerateNewRandomFile; i++) {
-    ASSERT_OK(Put("key" + RandomString(rnd, 7), RandomString(rnd, 2000)));
+    ASSERT_OK(Put("key" + rnd->RandomString(7), rnd->RandomString(2000)));
   }
-  ASSERT_OK(Put("key" + RandomString(rnd, 7), RandomString(rnd, 200)));
+  ASSERT_OK(Put("key" + rnd->RandomString(7), rnd->RandomString(200)));
   if (!nowait) {
     dbfull()->TEST_WaitForFlushMemTable();
     dbfull()->TEST_WaitForCompact();
diff --git a/db/db_test_util.h b/db/db_test_util.h
index 2dbf0fd6b..9a635139c 100644
--- a/db/db_test_util.h
+++ b/db/db_test_util.h
@@ -45,7 +45,6 @@
 #include "test_util/mock_time_env.h"
 #include "test_util/sync_point.h"
 #include "test_util/testharness.h"
-#include "test_util/testutil.h"
 #include "util/cast_util.h"
 #include "util/compression.h"
 #include "util/mutexlock.h"
@@ -876,12 +875,6 @@ class DBTestBase : public testing::Test {
 
   ~DBTestBase();
 
-  static std::string RandomString(Random* rnd, int len) {
-    std::string r;
-    test::RandomString(rnd, len, &r);
-    return r;
-  }
-
   static std::string Key(int i) {
     char buf[100];
     snprintf(buf, sizeof(buf), "key%06d", i);
diff --git a/db/db_universal_compaction_test.cc b/db/db_universal_compaction_test.cc
index 889e380dd..056af711d 100644
--- a/db/db_universal_compaction_test.cc
+++ b/db/db_universal_compaction_test.cc
@@ -12,6 +12,7 @@
 #if !defined(ROCKSDB_LITE)
 #include "rocksdb/utilities/table_properties_collectors.h"
 #include "test_util/sync_point.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -361,7 +362,7 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionSizeAmplification) {
        num++) {
     // Write 110KB (11 values, each 10K)
     for (int i = 0; i < 11; i++) {
-      ASSERT_OK(Put(1, Key(key_idx), RandomString(&rnd, 10000)));
+      ASSERT_OK(Put(1, Key(key_idx), rnd.RandomString(10000)));
       key_idx++;
     }
     dbfull()->TEST_WaitForFlushMemTable(handles_[1]);
@@ -419,7 +420,7 @@ TEST_P(DBTestUniversalCompaction, DynamicUniversalCompactionSizeAmplification) {
        num++) {
     // Write 110KB (11 values, each 10K)
     for (int i = 0; i < 11; i++) {
-      ASSERT_OK(Put(1, Key(key_idx), RandomString(&rnd, 10000)));
+      ASSERT_OK(Put(1, Key(key_idx), rnd.RandomString(10000)));
       key_idx++;
     }
     dbfull()->TEST_WaitForFlushMemTable(handles_[1]);
@@ -498,7 +499,7 @@ TEST_P(DBTestUniversalCompaction, DynamicUniversalCompactionReadAmplification) {
   for (int num = 0; num < options.level0_file_num_compaction_trigger; num++) {
     // Write 110KB (11 values, each 10K)
     for (int i = 0; i < 11; i++) {
-      ASSERT_OK(Put(1, Key(key_idx), RandomString(&rnd, 10000)));
+      ASSERT_OK(Put(1, Key(key_idx), rnd.RandomString(10000)));
       key_idx++;
     }
     dbfull()->TEST_WaitForFlushMemTable(handles_[1]);
@@ -576,7 +577,7 @@ TEST_P(DBTestUniversalCompaction, CompactFilesOnUniversalCompaction) {
   ASSERT_EQ(options.compaction_style, kCompactionStyleUniversal);
   Random rnd(301);
   for (int key = 1024 * kEntriesPerBuffer; key >= 0; --key) {
-    ASSERT_OK(Put(1, ToString(key), RandomString(&rnd, kTestValueSize)));
+    ASSERT_OK(Put(1, ToString(key), rnd.RandomString(kTestValueSize)));
   }
   dbfull()->TEST_WaitForFlushMemTable(handles_[1]);
   dbfull()->TEST_WaitForCompact();
@@ -639,17 +640,17 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionTargetLevel) {
   // Generate 3 overlapping files
   Random rnd(301);
   for (int i = 0; i < 210; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 100)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(100)));
   }
   ASSERT_OK(Flush());
 
   for (int i = 200; i < 300; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 100)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(100)));
   }
   ASSERT_OK(Flush());
 
   for (int i = 250; i < 260; i++) {
-    ASSERT_OK(Put(Key(i), RandomString(&rnd, 100)));
+    ASSERT_OK(Put(Key(i), rnd.RandomString(100)));
   }
   ASSERT_OK(Flush());
 
@@ -960,7 +961,7 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionOptions) {
   for (int num = 0; num < options.level0_file_num_compaction_trigger; num++) {
     // Write 100KB (100 values, each 1K)
     for (int i = 0; i < 100; i++) {
-      ASSERT_OK(Put(1, Key(key_idx), RandomString(&rnd, 990)));
+      ASSERT_OK(Put(1, Key(key_idx), rnd.RandomString(990)));
       key_idx++;
     }
     dbfull()->TEST_WaitForFlushMemTable(handles_[1]);
@@ -998,7 +999,7 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionStopStyleSimilarSize) {
        num++) {
     // Write 100KB (100 values, each 1K)
     for (int i = 0; i < 100; i++) {
-      ASSERT_OK(Put(Key(key_idx), RandomString(&rnd, 990)));
+      ASSERT_OK(Put(Key(key_idx), rnd.RandomString(990)));
       key_idx++;
     }
     dbfull()->TEST_WaitForFlushMemTable();
@@ -1008,7 +1009,7 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionStopStyleSimilarSize) {
   // Generate one more file at level-0, which should trigger level-0
   // compaction.
   for (int i = 0; i < 100; i++) {
-    ASSERT_OK(Put(Key(key_idx), RandomString(&rnd, 990)));
+    ASSERT_OK(Put(Key(key_idx), rnd.RandomString(990)));
     key_idx++;
   }
   dbfull()->TEST_WaitForCompact();
@@ -1029,7 +1030,7 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionStopStyleSimilarSize) {
        num++) {
     // Write 110KB (11 values, each 10K)
     for (int i = 0; i < 100; i++) {
-      ASSERT_OK(Put(Key(key_idx), RandomString(&rnd, 990)));
+      ASSERT_OK(Put(Key(key_idx), rnd.RandomString(990)));
       key_idx++;
     }
     dbfull()->TEST_WaitForFlushMemTable();
@@ -1039,7 +1040,7 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionStopStyleSimilarSize) {
   // Generate one more file at level-0, which should trigger level-0
   // compaction.
   for (int i = 0; i < 100; i++) {
-    ASSERT_OK(Put(Key(key_idx), RandomString(&rnd, 990)));
+    ASSERT_OK(Put(Key(key_idx), rnd.RandomString(990)));
     key_idx++;
   }
   dbfull()->TEST_WaitForCompact();
@@ -1050,7 +1051,7 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionStopStyleSimilarSize) {
   //   Now we have 3 files at level 0, with size 4, 0.4, 2. Generate one
   //   more file at level-0, which should trigger level-0 compaction.
   for (int i = 0; i < 100; i++) {
-    ASSERT_OK(Put(Key(key_idx), RandomString(&rnd, 990)));
+    ASSERT_OK(Put(Key(key_idx), rnd.RandomString(990)));
     key_idx++;
   }
   dbfull()->TEST_WaitForCompact();
@@ -1530,7 +1531,7 @@ TEST_P(DBTestUniversalCompaction, IncreaseUniversalCompactionNumLevels) {
 
   for (int i = 0; i <= max_key1; i++) {
     // each value is 10K
-    ASSERT_OK(Put(1, Key(i), RandomString(&rnd, 10000)));
+    ASSERT_OK(Put(1, Key(i), rnd.RandomString(10000)));
     dbfull()->TEST_WaitForFlushMemTable(handles_[1]);
     dbfull()->TEST_WaitForCompact();
   }
@@ -1548,7 +1549,7 @@ TEST_P(DBTestUniversalCompaction, IncreaseUniversalCompactionNumLevels) {
   // Insert more keys
   for (int i = max_key1 + 1; i <= max_key2; i++) {
     // each value is 10K
-    ASSERT_OK(Put(1, Key(i), RandomString(&rnd, 10000)));
+    ASSERT_OK(Put(1, Key(i), rnd.RandomString(10000)));
     dbfull()->TEST_WaitForFlushMemTable(handles_[1]);
     dbfull()->TEST_WaitForCompact();
   }
@@ -1580,7 +1581,7 @@ TEST_P(DBTestUniversalCompaction, IncreaseUniversalCompactionNumLevels) {
   // Insert more keys
   for (int i = max_key2 + 1; i <= max_key3; i++) {
     // each value is 10K
-    ASSERT_OK(Put(1, Key(i), RandomString(&rnd, 10000)));
+    ASSERT_OK(Put(1, Key(i), rnd.RandomString(10000)));
     dbfull()->TEST_WaitForFlushMemTable(handles_[1]);
     dbfull()->TEST_WaitForCompact();
   }
diff --git a/db/db_wal_test.cc b/db/db_wal_test.cc
index 5412cd4f4..537ee04a0 100644
--- a/db/db_wal_test.cc
+++ b/db/db_wal_test.cc
@@ -12,8 +12,8 @@
 #include "options/options_helper.h"
 #include "port/port.h"
 #include "port/stack_trace.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/sync_point.h"
+#include "utilities/fault_injection_env.h"
 
 namespace ROCKSDB_NAMESPACE {
 class DBWALTestBase : public DBTestBase {
diff --git a/db/db_with_timestamp_basic_test.cc b/db/db_with_timestamp_basic_test.cc
index a2a7313af..2a62fc533 100644
--- a/db/db_with_timestamp_basic_test.cc
+++ b/db/db_with_timestamp_basic_test.cc
@@ -13,10 +13,10 @@
 #include "rocksdb/utilities/debug.h"
 #include "table/block_based/block_based_table_reader.h"
 #include "table/block_based/block_builder.h"
-#include "test_util/fault_injection_test_env.h"
 #if !defined(ROCKSDB_LITE)
 #include "test_util/sync_point.h"
 #endif
+#include "utilities/fault_injection_env.h"
 
 namespace ROCKSDB_NAMESPACE {
 class DBBasicTestWithTimestampBase : public DBTestBase {
diff --git a/db/db_write_test.cc b/db/db_write_test.cc
index cc1aaac08..7910db70f 100644
--- a/db/db_write_test.cc
+++ b/db/db_write_test.cc
@@ -4,18 +4,20 @@
 //  (found in the LICENSE.Apache file in the root directory).
 
 #include <atomic>
+#include <fstream>
 #include <memory>
 #include <thread>
 #include <vector>
-#include <fstream>
+
 #include "db/db_test_util.h"
 #include "db/write_batch_internal.h"
 #include "db/write_thread.h"
 #include "port/port.h"
 #include "port/stack_trace.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/sync_point.h"
+#include "util/random.h"
 #include "util/string_util.h"
+#include "utilities/fault_injection_env.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -246,7 +248,7 @@ TEST_P(DBWriteTest, IOErrorOnSwitchMemtable) {
   mock_env->SetFilesystemActive(false, Status::IOError("Not active"));
   Status s;
   for (int i = 0; i < 4 * 512; ++i) {
-    s = Put(Key(i), RandomString(&rnd, 1024));
+    s = Put(Key(i), rnd.RandomString(1024));
     if (!s.ok()) {
       break;
     }
diff --git a/db/error_handler_fs_test.cc b/db/error_handler_fs_test.cc
index 912baa1ba..a944c6721 100644
--- a/db/error_handler_fs_test.cc
+++ b/db/error_handler_fs_test.cc
@@ -13,11 +13,12 @@
 #include "rocksdb/io_status.h"
 #include "rocksdb/perf_context.h"
 #include "rocksdb/sst_file_manager.h"
-#include "test_util/fault_injection_test_env.h"
-#include "test_util/fault_injection_test_fs.h"
 #if !defined(ROCKSDB_LITE)
 #include "test_util/sync_point.h"
 #endif
+#include "util/random.h"
+#include "utilities/fault_injection_env.h"
+#include "utilities/fault_injection_fs.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -744,7 +745,7 @@ TEST_F(DBErrorHandlingFSTest, WALWriteError) {
     WriteBatch batch;
 
     for (auto i = 0; i < 100; ++i) {
-      batch.Put(Key(i), RandomString(&rnd, 1024));
+      batch.Put(Key(i), rnd.RandomString(1024));
     }
 
     WriteOptions wopts;
@@ -757,7 +758,7 @@ TEST_F(DBErrorHandlingFSTest, WALWriteError) {
     int write_error = 0;
 
     for (auto i = 100; i < 199; ++i) {
-      batch.Put(Key(i), RandomString(&rnd, 1024));
+      batch.Put(Key(i), rnd.RandomString(1024));
     }
 
     SyncPoint::GetInstance()->SetCallBack(
@@ -820,7 +821,7 @@ TEST_F(DBErrorHandlingFSTest, WALWriteRetryableError) {
     WriteBatch batch;
 
     for (auto i = 0; i < 100; ++i) {
-      batch.Put(Key(i), RandomString(&rnd, 1024));
+      batch.Put(Key(i), rnd.RandomString(1024));
     }
 
     WriteOptions wopts;
@@ -835,7 +836,7 @@ TEST_F(DBErrorHandlingFSTest, WALWriteRetryableError) {
     int write_error = 0;
 
     for (auto i = 100; i < 200; ++i) {
-      batch.Put(Key(i), RandomString(&rnd, 1024));
+      batch.Put(Key(i), rnd.RandomString(1024));
     }
 
     SyncPoint::GetInstance()->SetCallBack(
@@ -871,7 +872,7 @@ TEST_F(DBErrorHandlingFSTest, WALWriteRetryableError) {
     WriteBatch batch;
 
     for (auto i = 200; i < 300; ++i) {
-      batch.Put(Key(i), RandomString(&rnd, 1024));
+      batch.Put(Key(i), rnd.RandomString(1024));
     }
 
     WriteOptions wopts;
@@ -912,7 +913,7 @@ TEST_F(DBErrorHandlingFSTest, MultiCFWALWriteError) {
 
     for (auto i = 1; i < 4; ++i) {
       for (auto j = 0; j < 100; ++j) {
-        batch.Put(handles_[i], Key(j), RandomString(&rnd, 1024));
+        batch.Put(handles_[i], Key(j), rnd.RandomString(1024));
       }
     }
 
@@ -927,7 +928,7 @@ TEST_F(DBErrorHandlingFSTest, MultiCFWALWriteError) {
 
     // Write to one CF
     for (auto i = 100; i < 199; ++i) {
-      batch.Put(handles_[2], Key(i), RandomString(&rnd, 1024));
+      batch.Put(handles_[2], Key(i), rnd.RandomString(1024));
     }
 
     SyncPoint::GetInstance()->SetCallBack(
@@ -1016,7 +1017,7 @@ TEST_F(DBErrorHandlingFSTest, MultiDBCompactionError) {
     WriteBatch batch;
 
     for (auto j = 0; j <= 100; ++j) {
-      batch.Put(Key(j), RandomString(&rnd, 1024));
+      batch.Put(Key(j), rnd.RandomString(1024));
     }
 
     WriteOptions wopts;
@@ -1031,7 +1032,7 @@ TEST_F(DBErrorHandlingFSTest, MultiDBCompactionError) {
 
     // Write to one CF
     for (auto j = 100; j < 199; ++j) {
-      batch.Put(Key(j), RandomString(&rnd, 1024));
+      batch.Put(Key(j), rnd.RandomString(1024));
     }
 
     WriteOptions wopts;
@@ -1129,7 +1130,7 @@ TEST_F(DBErrorHandlingFSTest, MultiDBVariousErrors) {
     WriteBatch batch;
 
     for (auto j = 0; j <= 100; ++j) {
-      batch.Put(Key(j), RandomString(&rnd, 1024));
+      batch.Put(Key(j), rnd.RandomString(1024));
     }
 
     WriteOptions wopts;
@@ -1144,7 +1145,7 @@ TEST_F(DBErrorHandlingFSTest, MultiDBVariousErrors) {
 
     // Write to one CF
     for (auto j = 100; j < 199; ++j) {
-      batch.Put(Key(j), RandomString(&rnd, 1024));
+      batch.Put(Key(j), rnd.RandomString(1024));
     }
 
     WriteOptions wopts;
diff --git a/db/external_sst_file_basic_test.cc b/db/external_sst_file_basic_test.cc
index 7e62963ec..26301c5ce 100644
--- a/db/external_sst_file_basic_test.cc
+++ b/db/external_sst_file_basic_test.cc
@@ -10,8 +10,9 @@
 #include "port/port.h"
 #include "port/stack_trace.h"
 #include "rocksdb/sst_file_writer.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/testutil.h"
+#include "util/random.h"
+#include "utilities/fault_injection_env.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -27,7 +28,7 @@ class ExternalSSTFileBasicTest
   }
 
   void DestroyAndRecreateExternalSSTFilesDir() {
-    test::DestroyDir(env_, sst_files_dir_);
+    DestroyDir(env_, sst_files_dir_);
     env_->CreateDir(sst_files_dir_);
   }
 
@@ -160,9 +161,7 @@ class ExternalSSTFileBasicTest
         write_global_seqno, verify_checksums_before_ingest, true_data);
   }
 
-  ~ExternalSSTFileBasicTest() override {
-    test::DestroyDir(env_, sst_files_dir_);
-  }
+  ~ExternalSSTFileBasicTest() override { DestroyDir(env_, sst_files_dir_); }
 
  protected:
   std::string sst_files_dir_;
@@ -1147,7 +1146,7 @@ TEST_F(ExternalSSTFileBasicTest, VerifyChecksumReadahead) {
   std::string file_name = sst_files_dir_ + "verify_checksum_readahead_test.sst";
   ASSERT_OK(sst_file_writer->Open(file_name));
   Random rnd(301);
-  std::string value = DBTestBase::RandomString(&rnd, 4000);
+  std::string value = rnd.RandomString(4000);
   for (int i = 0; i < 5000; i++) {
     ASSERT_OK(sst_file_writer->Put(DBTestBase::Key(i), value));
   }
diff --git a/db/external_sst_file_test.cc b/db/external_sst_file_test.cc
index 649bf7ac2..cd7757443 100644
--- a/db/external_sst_file_test.cc
+++ b/db/external_sst_file_test.cc
@@ -14,8 +14,9 @@
 #include "port/stack_trace.h"
 #include "rocksdb/sst_file_reader.h"
 #include "rocksdb/sst_file_writer.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/testutil.h"
+#include "util/random.h"
+#include "utilities/fault_injection_env.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -46,7 +47,7 @@ class ExternSSTFileLinkFailFallbackTest
       : DBTestBase("/external_sst_file_test"),
         test_env_(new ExternalSSTTestEnv(env_, true)) {
     sst_files_dir_ = dbname_ + "/sst_files/";
-    test::DestroyDir(env_, sst_files_dir_);
+    DestroyDir(env_, sst_files_dir_);
     env_->CreateDir(sst_files_dir_);
     options_ = CurrentOptions();
     options_.disable_auto_compactions = true;
@@ -77,7 +78,7 @@ class ExternalSSTFileTest
   }
 
   void DestroyAndRecreateExternalSSTFilesDir() {
-    test::DestroyDir(env_, sst_files_dir_);
+    DestroyDir(env_, sst_files_dir_);
     env_->CreateDir(sst_files_dir_);
   }
 
@@ -280,7 +281,7 @@ class ExternalSSTFileTest
     return db_->IngestExternalFile(files, opts);
   }
 
-  ~ExternalSSTFileTest() override { test::DestroyDir(env_, sst_files_dir_); }
+  ~ExternalSSTFileTest() override { DestroyDir(env_, sst_files_dir_); }
 
  protected:
   int last_file_id_ = 0;
@@ -1751,10 +1752,8 @@ TEST_P(ExternalSSTFileTest, IngestFileWithGlobalSeqnoRandomized) {
     for (int i = 0; i < 500; i++) {
       std::vector<std::pair<std::string, std::string>> random_data;
       for (int j = 0; j < 100; j++) {
-        std::string k;
-        std::string v;
-        test::RandomString(&rnd, rnd.Next() % 20, &k);
-        test::RandomString(&rnd, rnd.Next() % 50, &v);
+        std::string k = rnd.RandomString(rnd.Next() % 20);
+        std::string v = rnd.RandomString(rnd.Next() % 50);
         random_data.emplace_back(k, v);
       }
 
@@ -2388,8 +2387,7 @@ TEST_F(ExternalSSTFileTest, IngestFileWrittenWithCompressionDictionary) {
   Random rnd(301);
   std::vector<std::pair<std::string, std::string>> random_data;
   for (int i = 0; i < kNumEntries; i++) {
-    std::string val;
-    test::RandomString(&rnd, kNumBytesPerEntry, &val);
+    std::string val = rnd.RandomString(kNumBytesPerEntry);
     random_data.emplace_back(Key(i), std::move(val));
   }
   ASSERT_OK(GenerateAndAddExternalFile(options, std::move(random_data)));
@@ -2844,7 +2842,7 @@ TEST_P(ExternalSSTFileTest, DeltaEncodingWhileGlobalSeqnoPresent) {
   DestroyAndReopen(options);
   constexpr size_t kValueSize = 8;
   Random rnd(301);
-  std::string value(RandomString(&rnd, kValueSize));
+  std::string value = rnd.RandomString(kValueSize);
 
   // Write some key to make global seqno larger than zero
   for (int i = 0; i < 10; i++) {
@@ -2888,7 +2886,7 @@ TEST_P(ExternalSSTFileTest,
   Options options = CurrentOptions();
 
   Random rnd(301);
-  std::string value(RandomString(&rnd, kValueSize));
+  std::string value = rnd.RandomString(kValueSize);
 
   std::string key0 = "aa";
   std::string key1 = "ab";
diff --git a/db/fault_injection_test.cc b/db/fault_injection_test.cc
index f4ca3458a..7e208bbf9 100644
--- a/db/fault_injection_test.cc
+++ b/db/fault_injection_test.cc
@@ -22,11 +22,12 @@
 #include "rocksdb/env.h"
 #include "rocksdb/table.h"
 #include "rocksdb/write_batch.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/sync_point.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
 #include "util/mutexlock.h"
+#include "util/random.h"
+#include "utilities/fault_injection_env.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -249,7 +250,8 @@ class FaultInjectionTest
   // Return the value to associate with the specified key
   Slice Value(int k, std::string* storage) const {
     Random r(k);
-    return test::RandomString(&r, kValueSize, storage);
+    *storage = r.RandomString(kValueSize);
+    return Slice(*storage);
   }
 
   void CloseDB() {
diff --git a/db/flush_job_test.cc b/db/flush_job_test.cc
index 72cceb522..1f0fdef57 100644
--- a/db/flush_job_test.cc
+++ b/db/flush_job_test.cc
@@ -3,6 +3,8 @@
 //  COPYING file in the root directory) and Apache 2.0 License
 //  (found in the LICENSE.Apache file in the root directory).
 
+#include "db/flush_job.h"
+
 #include <algorithm>
 #include <array>
 #include <map>
@@ -11,7 +13,6 @@
 #include "db/blob/blob_index.h"
 #include "db/column_family.h"
 #include "db/db_impl/db_impl.h"
-#include "db/flush_job.h"
 #include "db/version_set.h"
 #include "file/writable_file_writer.h"
 #include "rocksdb/cache.h"
@@ -19,6 +20,7 @@
 #include "table/mock_table.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
+#include "util/random.h"
 #include "util/string_util.h"
 
 namespace ROCKSDB_NAMESPACE {
@@ -447,7 +449,7 @@ TEST_F(FlushJobTest, Snapshots) {
     std::string key(ToString(i));
     int insertions = rnd.Uniform(max_inserts_per_keys);
     for (int j = 0; j < insertions; ++j) {
-      std::string value(test::RandomHumanReadableString(&rnd, 10));
+      std::string value(rnd.HumanReadableString(10));
       auto seqno = ++current_seqno;
       new_mem->Add(SequenceNumber(seqno), kTypeValue, key, value);
       // a key is visible only if:
diff --git a/db/import_column_family_test.cc b/db/import_column_family_test.cc
index e17895b46..6961b3677 100644
--- a/db/import_column_family_test.cc
+++ b/db/import_column_family_test.cc
@@ -1,11 +1,13 @@
 #ifndef ROCKSDB_LITE
 
 #include <functional>
+
 #include "db/db_test_util.h"
 #include "port/port.h"
 #include "port/stack_trace.h"
 #include "rocksdb/sst_file_writer.h"
 #include "test_util/testutil.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -35,14 +37,14 @@ class ImportColumnFamilyTest : public DBTestBase {
       delete metadata_ptr_;
       metadata_ptr_ = nullptr;
     }
-    test::DestroyDir(env_, sst_files_dir_);
-    test::DestroyDir(env_, export_files_dir_);
+    DestroyDir(env_, sst_files_dir_);
+    DestroyDir(env_, export_files_dir_);
   }
 
   void DestroyAndRecreateExternalSSTFilesDir() {
-    test::DestroyDir(env_, sst_files_dir_);
+    DestroyDir(env_, sst_files_dir_);
     env_->CreateDir(sst_files_dir_);
-    test::DestroyDir(env_, export_files_dir_);
+    DestroyDir(env_, export_files_dir_);
   }
 
   LiveFileMetaData LiveFileMetaDataInit(std::string name, std::string path,
@@ -411,7 +413,7 @@ TEST_F(ImportColumnFamilyTest, ImportExportedSSTFromAnotherDB) {
 
   // Create a new db and import the files.
   DB* db_copy;
-  test::DestroyDir(env_, dbname_ + "/db_copy");
+  DestroyDir(env_, dbname_ + "/db_copy");
   ASSERT_OK(DB::Open(options, dbname_ + "/db_copy", &db_copy));
   ColumnFamilyHandle* cfh = nullptr;
   ASSERT_OK(db_copy->CreateColumnFamilyWithImport(ColumnFamilyOptions(), "yoyo",
@@ -427,7 +429,7 @@ TEST_F(ImportColumnFamilyTest, ImportExportedSSTFromAnotherDB) {
   db_copy->DropColumnFamily(cfh);
   db_copy->DestroyColumnFamilyHandle(cfh);
   delete db_copy;
-  test::DestroyDir(env_, dbname_ + "/db_copy");
+  DestroyDir(env_, dbname_ + "/db_copy");
 }
 
 TEST_F(ImportColumnFamilyTest, LevelFilesOverlappingAtEndpoints) {
@@ -450,7 +452,7 @@ TEST_F(ImportColumnFamilyTest, LevelFilesOverlappingAtEndpoints) {
   snapshots.reserve(kFileBytes / kValueBytes * kNumFiles);
   for (int i = 0; i < kNumFiles; ++i) {
     for (int j = 0; j < kFileBytes / kValueBytes; ++j) {
-      auto value = RandomString(&rnd, kValueBytes);
+      auto value = rnd.RandomString(kValueBytes);
       ASSERT_OK(Put(1, "key", value));
       snapshots.push_back(db_->GetSnapshot());
     }
@@ -471,7 +473,7 @@ TEST_F(ImportColumnFamilyTest, LevelFilesOverlappingAtEndpoints) {
 
   // Create a new db and import the files.
   DB* db_copy;
-  test::DestroyDir(env_, dbname_ + "/db_copy");
+  DestroyDir(env_, dbname_ + "/db_copy");
   ASSERT_OK(DB::Open(options, dbname_ + "/db_copy", &db_copy));
   ColumnFamilyHandle* cfh = nullptr;
   ASSERT_OK(db_copy->CreateColumnFamilyWithImport(ColumnFamilyOptions(), "yoyo",
@@ -486,7 +488,7 @@ TEST_F(ImportColumnFamilyTest, LevelFilesOverlappingAtEndpoints) {
   db_copy->DropColumnFamily(cfh);
   db_copy->DestroyColumnFamilyHandle(cfh);
   delete db_copy;
-  test::DestroyDir(env_, dbname_ + "/db_copy");
+  DestroyDir(env_, dbname_ + "/db_copy");
   for (const Snapshot* snapshot : snapshots) {
     db_->ReleaseSnapshot(snapshot);
   }
diff --git a/db/plain_table_db_test.cc b/db/plain_table_db_test.cc
index ea14f9a2a..dd428da9b 100644
--- a/db/plain_table_db_test.cc
+++ b/db/plain_table_db_test.cc
@@ -35,6 +35,7 @@
 #include "util/cast_util.h"
 #include "util/hash.h"
 #include "util/mutexlock.h"
+#include "util/random.h"
 #include "util/string_util.h"
 #include "utilities/merge_operators.h"
 
@@ -44,10 +45,10 @@ namespace ROCKSDB_NAMESPACE {
 class PlainTableKeyDecoderTest : public testing::Test {};
 
 TEST_F(PlainTableKeyDecoderTest, ReadNonMmap) {
-  std::string tmp;
   Random rnd(301);
   const uint32_t kLength = 2222;
-  Slice contents = test::RandomString(&rnd, kLength, &tmp);
+  std::string tmp = rnd.RandomString(kLength);
+  Slice contents(tmp);
   test::StringSource* string_source =
       new test::StringSource(contents, 0, false);
 
@@ -1267,12 +1268,6 @@ static std::string Key(int i) {
   return std::string(buf);
 }
 
-static std::string RandomString(Random* rnd, int len) {
-  std::string r;
-  test::RandomString(rnd, len, &r);
-  return r;
-}
-
 TEST_P(PlainTableDBTest, CompactionTrigger) {
   Options options = CurrentOptions();
   options.write_buffer_size = 120 << 10;  // 120KB
@@ -1287,7 +1282,7 @@ TEST_P(PlainTableDBTest, CompactionTrigger) {
     std::vector<std::string> values;
     // Write 120KB (10 values, each 12K)
     for (int i = 0; i < 10; i++) {
-      values.push_back(RandomString(&rnd, 12 << 10));
+      values.push_back(rnd.RandomString(12 << 10));
       ASSERT_OK(Put(Key(i), values[i]));
     }
     ASSERT_OK(Put(Key(999), ""));
@@ -1298,7 +1293,7 @@ TEST_P(PlainTableDBTest, CompactionTrigger) {
   //generate one more file in level-0, and should trigger level-0 compaction
   std::vector<std::string> values;
   for (int i = 0; i < 12; i++) {
-    values.push_back(RandomString(&rnd, 10000));
+    values.push_back(rnd.RandomString(10000));
     ASSERT_OK(Put(Key(i), values[i]));
   }
   ASSERT_OK(Put(Key(999), ""));
diff --git a/db_stress_tool/cf_consistency_stress.cc b/db_stress_tool/cf_consistency_stress.cc
index c6ba5d699..acddae159 100644
--- a/db_stress_tool/cf_consistency_stress.cc
+++ b/db_stress_tool/cf_consistency_stress.cc
@@ -9,6 +9,7 @@
 
 #ifdef GFLAGS
 #include "db_stress_tool/db_stress_common.h"
+#include "file/file_util.h"
 
 namespace ROCKSDB_NAMESPACE {
 class CfConsistencyStressTest : public StressTest {
@@ -307,7 +308,7 @@ class CfConsistencyStressTest : public StressTest {
     if (db_stress_env->FileExists(checkpoint_dir).ok()) {
       // If the directory might still exist, try to delete the files one by one.
       // Likely a trash file is still there.
-      Status my_s = test::DestroyDir(db_stress_env, checkpoint_dir);
+      Status my_s = DestroyDir(db_stress_env, checkpoint_dir);
       if (!my_s.ok()) {
         fprintf(stderr, "Fail to destory directory before checkpoint: %s",
                 my_s.ToString().c_str());
diff --git a/db_stress_tool/db_stress_common.h b/db_stress_tool/db_stress_common.h
index 8c9c9bfa6..f4654cbb5 100644
--- a/db_stress_tool/db_stress_common.h
+++ b/db_stress_tool/db_stress_common.h
@@ -26,6 +26,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/types.h>
+
 #include <algorithm>
 #include <array>
 #include <chrono>
@@ -58,9 +59,7 @@
 #include "rocksdb/utilities/transaction.h"
 #include "rocksdb/utilities/transaction_db.h"
 #include "rocksdb/write_batch.h"
-#ifndef NDEBUG
-#include "test_util/fault_injection_test_fs.h"
-#endif
+#include "test_util/testutil.h"
 #include "util/coding.h"
 #include "util/compression.h"
 #include "util/crc32c.h"
@@ -69,9 +68,6 @@
 #include "util/random.h"
 #include "util/string_util.h"
 #include "utilities/blob_db/blob_db.h"
-#include "test_util/testutil.h"
-#include "test_util/fault_injection_test_env.h"
-
 #include "utilities/merge_operators.h"
 
 using GFLAGS_NAMESPACE::ParseCommandLineFlags;
@@ -248,6 +244,9 @@ const int kValueMaxLen = 100;
 // wrapped posix or hdfs environment
 extern ROCKSDB_NAMESPACE::DbStressEnvWrapper* db_stress_env;
 #ifndef NDEBUG
+namespace ROCKSDB_NAMESPACE {
+class FaultInjectionTestFS;
+}  // namespace ROCKSDB_NAMESPACE
 extern std::shared_ptr<ROCKSDB_NAMESPACE::FaultInjectionTestFS> fault_fs_guard;
 #endif
 
diff --git a/db_stress_tool/db_stress_driver.cc b/db_stress_tool/db_stress_driver.cc
index 0ae848049..69411aa29 100644
--- a/db_stress_tool/db_stress_driver.cc
+++ b/db_stress_tool/db_stress_driver.cc
@@ -10,6 +10,7 @@
 
 #ifdef GFLAGS
 #include "db_stress_tool/db_stress_common.h"
+#include "utilities/fault_injection_fs.h"
 
 namespace ROCKSDB_NAMESPACE {
 void ThreadBody(void* v) {
diff --git a/db_stress_tool/db_stress_test_base.cc b/db_stress_tool/db_stress_test_base.cc
index 481a7bfd7..723517040 100644
--- a/db_stress_tool/db_stress_test_base.cc
+++ b/db_stress_tool/db_stress_test_base.cc
@@ -15,6 +15,7 @@
 #include "rocksdb/convenience.h"
 #include "rocksdb/sst_file_manager.h"
 #include "util/cast_util.h"
+#include "utilities/fault_injection_fs.h"
 
 namespace ROCKSDB_NAMESPACE {
 StressTest::StressTest()
@@ -1341,7 +1342,7 @@ Status StressTest::TestCheckpoint(ThreadState* thread,
   if (db_stress_env->FileExists(checkpoint_dir).ok()) {
     // If the directory might still exist, try to delete the files one by one.
     // Likely a trash file is still there.
-    Status my_s = test::DestroyDir(db_stress_env, checkpoint_dir);
+    Status my_s = DestroyDir(db_stress_env, checkpoint_dir);
     if (!my_s.ok()) {
       fprintf(stderr, "Fail to destory directory before checkpoint: %s",
               my_s.ToString().c_str());
diff --git a/db_stress_tool/db_stress_tool.cc b/db_stress_tool/db_stress_tool.cc
index 498462e56..3e950726b 100644
--- a/db_stress_tool/db_stress_tool.cc
+++ b/db_stress_tool/db_stress_tool.cc
@@ -24,7 +24,7 @@
 #include "db_stress_tool/db_stress_common.h"
 #include "db_stress_tool/db_stress_driver.h"
 #ifndef NDEBUG
-#include "test_util/fault_injection_test_fs.h"
+#include "utilities/fault_injection_fs.h"
 #endif
 
 namespace ROCKSDB_NAMESPACE {
@@ -47,7 +47,7 @@ int db_stress_tool(int argc, char** argv) {
 
 #ifndef NDEBUG
   if (FLAGS_mock_direct_io) {
-    test::SetupSyncPointsToMockDirectIO();
+    SetupSyncPointsToMockDirectIO();
   }
 #endif
   if (FLAGS_statistics) {
diff --git a/db_stress_tool/no_batched_ops_stress.cc b/db_stress_tool/no_batched_ops_stress.cc
index 654f0c974..269d0886d 100644
--- a/db_stress_tool/no_batched_ops_stress.cc
+++ b/db_stress_tool/no_batched_ops_stress.cc
@@ -10,7 +10,7 @@
 #ifdef GFLAGS
 #include "db_stress_tool/db_stress_common.h"
 #ifndef NDEBUG
-#include "test_util/fault_injection_test_fs.h"
+#include "utilities/fault_injection_fs.h"
 #endif // NDEBUG
 
 namespace ROCKSDB_NAMESPACE {
diff --git a/env/env_test.cc b/env/env_test.cc
index 714422472..73b5c95a6 100644
--- a/env/env_test.cc
+++ b/env/env_test.cc
@@ -35,14 +35,15 @@
 #include "port/malloc.h"
 #include "port/port.h"
 #include "rocksdb/env.h"
-#include "test_util/fault_injection_test_env.h"
-#include "test_util/fault_injection_test_fs.h"
 #include "test_util/sync_point.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
 #include "util/coding.h"
 #include "util/mutexlock.h"
+#include "util/random.h"
 #include "util/string_util.h"
+#include "utilities/fault_injection_env.h"
+#include "utilities/fault_injection_fs.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -287,7 +288,7 @@ TEST_F(EnvPosixTest, MemoryMappedFileBuffer) {
     ASSERT_OK(env_->NewWritableFile(fname, &wfile, soptions));
 
     Random rnd(301);
-    test::RandomString(&rnd, kFileBytes, &expected_data);
+    expected_data = rnd.RandomString(kFileBytes);
     ASSERT_OK(wfile->Append(expected_data));
   }
 
@@ -1264,9 +1265,8 @@ TEST_F(EnvPosixTest, MultiReadNonAlignedLargeNum) {
   std::string fname = test::PerThreadDBPath(env_, "testfile");
 
   const size_t kTotalSize = 81920;
-  std::string expected_data;
   Random rnd(301);
-  test::RandomString(&rnd, kTotalSize, &expected_data);
+  std::string expected_data = rnd.RandomString(kTotalSize);
 
   // Create file.
   {
@@ -1949,7 +1949,7 @@ TEST_P(EnvPosixTestWithParam, PosixRandomRWFileRandomized) {
   std::string buf;
   for (int i = 0; i < 10000; i++) {
     // Genrate random data
-    test::RandomString(&rnd, 10, &buf);
+    buf = rnd.RandomString(10);
 
     // Pick random offset for write
     size_t write_off = rnd.Next() % 1000;
diff --git a/file/delete_scheduler_test.cc b/file/delete_scheduler_test.cc
index 993fba12a..67eaa50e6 100644
--- a/file/delete_scheduler_test.cc
+++ b/file/delete_scheduler_test.cc
@@ -3,18 +3,20 @@
 //  COPYING file in the root directory) and Apache 2.0 License
 //  (found in the LICENSE.Apache file in the root directory).
 
+#include "file/delete_scheduler.h"
+
 #include <atomic>
 #include <cinttypes>
 #include <thread>
 #include <vector>
 
-#include "file/delete_scheduler.h"
+#include "env/composite_env_wrapper.h"
+#include "file/file_util.h"
 #include "file/sst_file_manager_impl.h"
 #include "rocksdb/env.h"
 #include "rocksdb/options.h"
 #include "test_util/sync_point.h"
 #include "test_util/testharness.h"
-#include "test_util/testutil.h"
 #include "util/string_util.h"
 
 #ifndef ROCKSDB_LITE
@@ -40,12 +42,12 @@ class DeleteSchedulerTest : public testing::Test {
     ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->LoadDependency({});
     ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->ClearAllCallBacks();
     for (const auto& dummy_files_dir : dummy_files_dirs_) {
-      test::DestroyDir(env_, dummy_files_dir);
+      DestroyDir(env_, dummy_files_dir);
     }
   }
 
   void DestroyAndCreateDir(const std::string& dir) {
-    ASSERT_OK(test::DestroyDir(env_, dir));
+    ASSERT_OK(DestroyDir(env_, dir));
     EXPECT_OK(env_->CreateDir(dir));
   }
 
diff --git a/file/file_util.cc b/file/file_util.cc
index 70178a0bd..0fda7aa83 100644
--- a/file/file_util.cc
+++ b/file/file_util.cc
@@ -187,4 +187,49 @@ IOStatus GenerateOneFileChecksum(FileSystem* fs, const std::string& file_path,
   return IOStatus::OK();
 }
 
+Status DestroyDir(Env* env, const std::string& dir) {
+  Status s;
+  if (env->FileExists(dir).IsNotFound()) {
+    return s;
+  }
+  std::vector<std::string> files_in_dir;
+  s = env->GetChildren(dir, &files_in_dir);
+  if (s.ok()) {
+    for (auto& file_in_dir : files_in_dir) {
+      if (file_in_dir == "." || file_in_dir == "..") {
+        continue;
+      }
+      std::string path = dir + "/" + file_in_dir;
+      bool is_dir = false;
+      s = env->IsDirectory(path, &is_dir);
+      if (s.ok()) {
+        if (is_dir) {
+          s = DestroyDir(env, path);
+        } else {
+          s = env->DeleteFile(path);
+        }
+      }
+      if (!s.ok()) {
+        // IsDirectory, etc. might not report NotFound
+        if (s.IsNotFound() || env->FileExists(path).IsNotFound()) {
+          // Allow files to be deleted externally
+          s = Status::OK();
+        } else {
+          break;
+        }
+      }
+    }
+  }
+
+  if (s.ok()) {
+    s = env->DeleteDir(dir);
+    // DeleteDir might or might not report NotFound
+    if (!s.ok() && (s.IsNotFound() || env->FileExists(dir).IsNotFound())) {
+      // Allow to be deleted externally
+      s = Status::OK();
+    }
+  }
+  return s;
+}
+
 }  // namespace ROCKSDB_NAMESPACE
diff --git a/file/file_util.h b/file/file_util.h
index ac7257e05..1f77b760a 100644
--- a/file/file_util.h
+++ b/file/file_util.h
@@ -53,4 +53,7 @@ inline IOStatus PrepareIOFromReadOptions(const ReadOptions& ro, Env* env,
   return IOStatus::OK();
 }
 
+// Test method to delete the input directory and all of its contents.
+// This method is destructive and is meant for use only in tests!!!
+Status DestroyDir(Env* env, const std::string& dir);
 }  // namespace ROCKSDB_NAMESPACE
diff --git a/file/random_access_file_reader_test.cc b/file/random_access_file_reader_test.cc
index 7580cdd72..a8be671a5 100644
--- a/file/random_access_file_reader_test.cc
+++ b/file/random_access_file_reader_test.cc
@@ -3,19 +3,22 @@
 //  COPYING file in the root directory) and Apache 2.0 License
 //  (found in the LICENSE.Apache file in the root directory).
 
+#include "file/random_access_file_reader.h"
+
+#include "file/file_util.h"
 #include "port/port.h"
 #include "port/stack_trace.h"
 #include "rocksdb/file_system.h"
-#include "file/random_access_file_reader.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
 class RandomAccessFileReaderTest : public testing::Test {
  public:
   void SetUp() override {
-    test::SetupSyncPointsToMockDirectIO();
+    SetupSyncPointsToMockDirectIO();
     env_ = Env::Default();
     fs_ = FileSystem::Default();
     test_dir_ = test::PerThreadDBPath("random_access_file_reader_test");
@@ -23,9 +26,7 @@ class RandomAccessFileReaderTest : public testing::Test {
     ComputeAndSetAlignment();
   }
 
-  void TearDown() override {
-    EXPECT_OK(test::DestroyDir(env_, test_dir_));
-  }
+  void TearDown() override { EXPECT_OK(DestroyDir(env_, test_dir_)); }
 
   void Write(const std::string& fname, const std::string& content) {
     std::unique_ptr<FSWritableFile> f;
@@ -79,8 +80,7 @@ class RandomAccessFileReaderTest : public testing::Test {
 TEST_F(RandomAccessFileReaderTest, ReadDirectIO) {
   std::string fname = "read-direct-io";
   Random rand(0);
-  std::string content;
-  test::RandomString(&rand, static_cast<int>(alignment()), &content);
+  std::string content = rand.RandomString(static_cast<int>(alignment()));
   Write(fname, content);
 
   FileOptions opts;
@@ -104,8 +104,7 @@ TEST_F(RandomAccessFileReaderTest, MultiReadDirectIO) {
   // Creates a file with 3 pages.
   std::string fname = "multi-read-direct-io";
   Random rand(0);
-  std::string content;
-  test::RandomString(&rand, 3 * static_cast<int>(alignment()), &content);
+  std::string content = rand.RandomString(3 * static_cast<int>(alignment()));
   Write(fname, content);
 
   FileOptions opts;
diff --git a/memtable/memtablerep_bench.cc b/memtable/memtablerep_bench.cc
index cbe62cc85..0f6203042 100644
--- a/memtable/memtablerep_bench.cc
+++ b/memtable/memtablerep_bench.cc
@@ -141,7 +141,7 @@ class RandomGenerator {
   RandomGenerator() {
     Random rnd(301);
     auto size = (unsigned)std::max(1048576, FLAGS_item_size);
-    test::RandomString(&rnd, size, &data_);
+    data_ = rnd.RandomString(size);
     pos_ = 0;
   }
 
diff --git a/src.mk b/src.mk
index c4fec346e..2e438f9df 100644
--- a/src.mk
+++ b/src.mk
@@ -212,6 +212,8 @@ LIB_SOURCES =                                                   \
   utilities/debug.cc                                            \
   utilities/env_mirror.cc                                       \
   utilities/env_timed.cc                                        \
+  utilities/fault_injection_env.cc                              \
+  utilities/fault_injection_fs.cc                               \
   utilities/leveldb_options/leveldb_options.cc                  \
   utilities/memory/memory_util.cc                               \
   utilities/merge_operators/max.cc                              \
@@ -277,8 +279,6 @@ ANALYZER_LIB_SOURCES =                                          \
 
 MOCK_LIB_SOURCES =                                              \
   table/mock_table.cc                                           \
-  test_util/fault_injection_test_fs.cc                          \
-  test_util/fault_injection_test_env.cc
 
 BENCH_LIB_SOURCES =                                             \
   tools/db_bench_tool.cc                                        \
diff --git a/table/block_based/block_based_table_reader_test.cc b/table/block_based/block_based_table_reader_test.cc
index 6062b3d4e..e46e3de11 100644
--- a/table/block_based/block_based_table_reader_test.cc
+++ b/table/block_based/block_based_table_reader_test.cc
@@ -4,18 +4,20 @@
 //  (found in the LICENSE.Apache file in the root directory).
 
 #include "table/block_based/block_based_table_reader.h"
-#include "rocksdb/file_system.h"
-#include "table/block_based/partitioned_index_iterator.h"
 
 #include "db/table_properties_collector.h"
+#include "file/file_util.h"
 #include "options/options_helper.h"
 #include "port/port.h"
 #include "port/stack_trace.h"
+#include "rocksdb/file_system.h"
 #include "table/block_based/block_based_table_builder.h"
 #include "table/block_based/block_based_table_factory.h"
+#include "table/block_based/partitioned_index_iterator.h"
 #include "table/format.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -33,7 +35,7 @@ class BlockBasedTableReaderTest
     std::tie(compression_type_, use_direct_reads_, index_type, no_block_cache) =
         GetParam();
 
-    test::SetupSyncPointsToMockDirectIO();
+    SetupSyncPointsToMockDirectIO();
     test_dir_ = test::PerThreadDBPath("block_based_table_reader_test");
     env_ = Env::Default();
     fs_ = FileSystem::Default();
@@ -46,7 +48,7 @@ class BlockBasedTableReaderTest
         static_cast<BlockBasedTableFactory*>(NewBlockBasedTableFactory(opts)));
   }
 
-  void TearDown() override { EXPECT_OK(test::DestroyDir(env_, test_dir_)); }
+  void TearDown() override { EXPECT_OK(DestroyDir(env_, test_dir_)); }
 
   // Creates a table with the specificied key value pairs (kv).
   void CreateTable(const std::string& table_name,
@@ -159,9 +161,9 @@ TEST_P(BlockBasedTableReaderTest, MultiGet) {
         sprintf(k, "%08u", key);
         std::string v;
         if (block % 2) {
-          v = test::RandomHumanReadableString(&rnd, 256);
+          v = rnd.HumanReadableString(256);
         } else {
-          test::RandomString(&rnd, 256, &v);
+          v = rnd.RandomString(256);
         }
         kv[std::string(k)] = v;
         key++;
@@ -256,8 +258,7 @@ TEST_P(BlockBasedTableReaderTestVerifyChecksum, ChecksumMismatch) {
         // and internal key size is required to be >= 8 bytes,
         // so use %08u as the format string.
         sprintf(k, "%08u", key);
-        std::string v;
-        test::RandomString(&rnd, 256, &v);
+        std::string v = rnd.RandomString(256);
         kv[std::string(k)] = v;
         key++;
       }
diff --git a/table/block_based/block_test.cc b/table/block_based/block_test.cc
index 7521c1515..c9f12d54e 100644
--- a/table/block_based/block_test.cc
+++ b/table/block_based/block_test.cc
@@ -29,12 +29,6 @@
 
 namespace ROCKSDB_NAMESPACE {
 
-static std::string RandomString(Random *rnd, int len) {
-  std::string r;
-  test::RandomString(rnd, len, &r);
-  return r;
-}
-
 std::string GenerateInternalKey(int primary_key, int secondary_key,
                                 int padding_size, Random *rnd) {
   char buf[50];
@@ -42,7 +36,7 @@ std::string GenerateInternalKey(int primary_key, int secondary_key,
   snprintf(buf, sizeof(buf), "%6d%4d", primary_key, secondary_key);
   std::string k(p);
   if (padding_size) {
-    k += RandomString(rnd, padding_size);
+    k += rnd->RandomString(padding_size);
   }
   AppendInternalKeyFooter(&k, 0 /* seqno */, kTypeValue);
 
@@ -67,7 +61,7 @@ void GenerateRandomKVs(std::vector<std::string> *keys,
       keys->emplace_back(GenerateInternalKey(i, j, padding_size, &rnd));
 
       // 100 bytes values
-      values->emplace_back(RandomString(&rnd, 100));
+      values->emplace_back(rnd.RandomString(100));
     }
   }
 }
diff --git a/table/block_based/data_block_hash_index_test.cc b/table/block_based/data_block_hash_index_test.cc
index 409a5bdc2..94fa7e94f 100644
--- a/table/block_based/data_block_hash_index_test.cc
+++ b/table/block_based/data_block_hash_index_test.cc
@@ -3,6 +3,8 @@
 //  COPYING file in the root directory) and Apache 2.0 License
 //  (found in the LICENSE.Apache file in the root directory).
 
+#include "table/block_based/data_block_hash_index.h"
+
 #include <cstdlib>
 #include <string>
 #include <unordered_map>
@@ -12,11 +14,11 @@
 #include "table/block_based/block.h"
 #include "table/block_based/block_based_table_reader.h"
 #include "table/block_based/block_builder.h"
-#include "table/block_based/data_block_hash_index.h"
 #include "table/get_context.h"
 #include "table/table_builder.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -35,12 +37,6 @@ bool SearchForOffset(DataBlockHashIndex& index, const char* data,
   return entry == restart_point;
 }
 
-// Random KV generator similer to block_test
-static std::string RandomString(Random* rnd, int len) {
-  std::string r;
-  test::RandomString(rnd, len, &r);
-  return r;
-}
 std::string GenerateKey(int primary_key, int secondary_key, int padding_size,
                         Random* rnd) {
   char buf[50];
@@ -48,7 +44,7 @@ std::string GenerateKey(int primary_key, int secondary_key, int padding_size,
   snprintf(buf, sizeof(buf), "%6d%4d", primary_key, secondary_key);
   std::string k(p);
   if (padding_size) {
-    k += RandomString(rnd, padding_size);
+    k += rnd->RandomString(padding_size);
   }
 
   return k;
@@ -71,7 +67,7 @@ void GenerateRandomKVs(std::vector<std::string>* keys,
       keys->emplace_back(GenerateKey(i, j, padding_size, &rnd));
 
       // 100 bytes values
-      values->emplace_back(RandomString(&rnd, 100));
+      values->emplace_back(rnd.RandomString(100));
     }
   }
 }
diff --git a/table/block_fetcher_test.cc b/table/block_fetcher_test.cc
index 6d1cd5ddd..e3c17b292 100644
--- a/table/block_fetcher_test.cc
+++ b/table/block_fetcher_test.cc
@@ -4,7 +4,10 @@
 //  (found in the LICENSE.Apache file in the root directory).
 
 #include "table/block_fetcher.h"
+
 #include "db/table_properties_collector.h"
+#include "env/composite_env_wrapper.h"
+#include "file/file_util.h"
 #include "options/options_helper.h"
 #include "port/port.h"
 #include "port/stack_trace.h"
@@ -14,7 +17,6 @@
 #include "table/block_based/block_based_table_reader.h"
 #include "table/format.h"
 #include "test_util/testharness.h"
-#include "test_util/testutil.h"
 
 namespace ROCKSDB_NAMESPACE {
 namespace {
@@ -71,14 +73,14 @@ class BlockFetcherTest : public testing::Test {
 
  protected:
   void SetUp() override {
-    test::SetupSyncPointsToMockDirectIO();
+    SetupSyncPointsToMockDirectIO();
     test_dir_ = test::PerThreadDBPath("block_fetcher_test");
     env_ = Env::Default();
     fs_ = FileSystem::Default();
     ASSERT_OK(fs_->CreateDir(test_dir_, IOOptions(), nullptr));
   }
 
-  void TearDown() override { EXPECT_OK(test::DestroyDir(env_, test_dir_)); }
+  void TearDown() override { EXPECT_OK(DestroyDir(env_, test_dir_)); }
 
   void AssertSameBlock(const std::string& block1, const std::string& block2) {
     ASSERT_EQ(block1, block2);
diff --git a/table/merger_test.cc b/table/merger_test.cc
index 466e0eb42..13f225731 100644
--- a/table/merger_test.cc
+++ b/table/merger_test.cc
@@ -3,12 +3,13 @@
 //  COPYING file in the root directory) and Apache 2.0 License
 //  (found in the LICENSE.Apache file in the root directory).
 
-#include <vector>
 #include <string>
+#include <vector>
 
 #include "table/merging_iterator.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -24,7 +25,7 @@ class MergerTest : public testing::Test {
     std::vector<std::string> ret;
 
     for (size_t i = 0; i < len; ++i) {
-      InternalKey ik(test::RandomHumanReadableString(&rnd_, string_len), 0,
+      InternalKey ik(rnd_.HumanReadableString(string_len), 0,
                      ValueType::kTypeValue);
       ret.push_back(ik.Encode().ToString(false));
     }
@@ -44,8 +45,7 @@ class MergerTest : public testing::Test {
   }
 
   void SeekToRandom() {
-    InternalKey ik(test::RandomHumanReadableString(&rnd_, 5), 0,
-                   ValueType::kTypeValue);
+    InternalKey ik(rnd_.HumanReadableString(5), 0, ValueType::kTypeValue);
     Seek(ik.Encode().ToString(false));
   }
 
diff --git a/table/table_test.cc b/table/table_test.cc
index 7bc53a584..3554f3463 100644
--- a/table/table_test.cc
+++ b/table/table_test.cc
@@ -1227,8 +1227,7 @@ class FileChecksumTestHelper {
   void AddKVtoKVMap(int num_entries) {
     Random rnd(test::RandomSeed());
     for (int i = 0; i < num_entries; i++) {
-      std::string v;
-      test::RandomString(&rnd, 100, &v);
+      std::string v = rnd.RandomString(100);
       kv_map_[test::RandomKey(&rnd, 20)] = v;
     }
   }
@@ -1899,16 +1898,10 @@ TEST_P(BlockBasedTableTest, SkipPrefixBloomFilter) {
   }
 }
 
-static std::string RandomString(Random* rnd, int len) {
-  std::string r;
-  test::RandomString(rnd, len, &r);
-  return r;
-}
-
 void AddInternalKey(TableConstructor* c, const std::string& prefix,
                     std::string value = "v", int /*suffix_len*/ = 800) {
   static Random rnd(1023);
-  InternalKey k(prefix + RandomString(&rnd, 800), 0, kTypeValue);
+  InternalKey k(prefix + rnd.RandomString(800), 0, kTypeValue);
   c->Add(k.Encode().ToString(), value);
 }
 
@@ -2481,7 +2474,7 @@ TEST_P(BlockBasedTableTest, IndexSizeStat) {
   std::vector<std::string> keys;
 
   for (int i = 0; i < 100; ++i) {
-    keys.push_back(RandomString(&rnd, 10000));
+    keys.push_back(rnd.RandomString(10000));
   }
 
   // Each time we load one more key to the table. the table index block
@@ -2525,7 +2518,7 @@ TEST_P(BlockBasedTableTest, NumBlockStat) {
   for (int i = 0; i < 10; ++i) {
     // the key/val are slightly smaller than block size, so that each block
     // holds roughly one key/value pair.
-    c.Add(RandomString(&rnd, 900), "val");
+    c.Add(rnd.RandomString(900), "val");
   }
 
   std::vector<std::string> ks;
@@ -3607,9 +3600,8 @@ TEST_P(ParameterizedHarnessTest, RandomizedHarnessTest) {
   for (int num_entries = 0; num_entries < 2000;
        num_entries += (num_entries < 50 ? 1 : 200)) {
     for (int e = 0; e < num_entries; e++) {
-      std::string v;
       Add(test::RandomKey(&rnd, rnd.Skewed(4)),
-          test::RandomString(&rnd, rnd.Skewed(5), &v).ToString());
+          rnd.RandomString(rnd.Skewed(5)));
     }
     Test(&rnd);
   }
@@ -3621,8 +3613,7 @@ TEST_F(DBHarnessTest, RandomizedLongDB) {
   int num_entries = 100000;
   for (int e = 0; e < num_entries; e++) {
     std::string v;
-    Add(test::RandomKey(&rnd, rnd.Skewed(4)),
-        test::RandomString(&rnd, rnd.Skewed(5), &v).ToString());
+    Add(test::RandomKey(&rnd, rnd.Skewed(4)), rnd.RandomString(rnd.Skewed(5)));
   }
   Test(&rnd);
 
@@ -3878,8 +3869,8 @@ TEST_P(IndexBlockRestartIntervalTest, IndexBlockRestartInterval) {
   TableConstructor c(BytewiseComparator());
   static Random rnd(301);
   for (int i = 0; i < kKeysInTable; i++) {
-    InternalKey k(RandomString(&rnd, kKeySize), 0, kTypeValue);
-    c.Add(k.Encode().ToString(), RandomString(&rnd, kValSize));
+    InternalKey k(rnd.RandomString(kKeySize), 0, kTypeValue);
+    c.Add(k.Encode().ToString(), rnd.RandomString(kValSize));
   }
 
   std::vector<std::string> keys;
@@ -4541,9 +4532,9 @@ TEST_P(BlockBasedTableTest, DataBlockHashIndex) {
   static Random rnd(1048);
   for (int i = 0; i < kNumKeys; i++) {
     // padding one "0" to mark existent keys.
-    std::string random_key(RandomString(&rnd, kKeySize - 1) + "1");
+    std::string random_key(rnd.RandomString(kKeySize - 1) + "1");
     InternalKey k(random_key, 0, kTypeValue);
-    c.Add(k.Encode().ToString(), RandomString(&rnd, kValSize));
+    c.Add(k.Encode().ToString(), rnd.RandomString(kValSize));
   }
 
   std::vector<std::string> keys;
diff --git a/test_util/sync_point.cc b/test_util/sync_point.cc
index 345e41d64..afdda872b 100644
--- a/test_util/sync_point.cc
+++ b/test_util/sync_point.cc
@@ -4,6 +4,10 @@
 //  (found in the LICENSE.Apache file in the root directory).
 
 #include "test_util/sync_point.h"
+
+#include <fcntl.h>
+#include <sys/stat.h>
+
 #include "test_util/sync_point_impl.h"
 
 int rocksdb_kill_odds = 0;
@@ -64,3 +68,22 @@ void SyncPoint::Process(const std::string& point, void* cb_arg) {
 
 }  // namespace ROCKSDB_NAMESPACE
 #endif  // NDEBUG
+
+namespace ROCKSDB_NAMESPACE {
+void SetupSyncPointsToMockDirectIO() {
+#if !defined(NDEBUG) && !defined(OS_MACOSX) && !defined(OS_WIN) && \
+    !defined(OS_SOLARIS) && !defined(OS_AIX) && !defined(OS_OPENBSD)
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
+      "NewWritableFile:O_DIRECT", [&](void* arg) {
+        int* val = static_cast<int*>(arg);
+        *val &= ~O_DIRECT;
+      });
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
+      "NewRandomAccessFile:O_DIRECT", [&](void* arg) {
+        int* val = static_cast<int*>(arg);
+        *val &= ~O_DIRECT;
+      });
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
+#endif
+}
+}  // namespace ROCKSDB_NAMESPACE
diff --git a/test_util/sync_point.h b/test_util/sync_point.h
index 007510a4f..08d6c037a 100644
--- a/test_util/sync_point.h
+++ b/test_util/sync_point.h
@@ -124,6 +124,9 @@ class SyncPoint {
   Data*  impl_;
 };
 
+// Sets up sync points to mock direct IO instead of actually issuing direct IO
+// to the file system.
+void SetupSyncPointsToMockDirectIO();
 }  // namespace ROCKSDB_NAMESPACE
 
 // Use TEST_SYNC_POINT to specify sync points inside code base.
diff --git a/test_util/testutil.cc b/test_util/testutil.cc
index 0d95e3feb..234c76d81 100644
--- a/test_util/testutil.cc
+++ b/test_util/testutil.cc
@@ -11,6 +11,7 @@
 
 #include <fcntl.h>
 #include <sys/stat.h>
+
 #include <array>
 #include <cctype>
 #include <fstream>
@@ -23,6 +24,7 @@
 #include "file/writable_file_writer.h"
 #include "port/port.h"
 #include "test_util/sync_point.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 namespace test {
@@ -30,23 +32,6 @@ namespace test {
 const uint32_t kDefaultFormatVersion = BlockBasedTableOptions().format_version;
 const uint32_t kLatestFormatVersion = 5u;
 
-Slice RandomString(Random* rnd, int len, std::string* dst) {
-  dst->resize(len);
-  for (int i = 0; i < len; i++) {
-    (*dst)[i] = static_cast<char>(' ' + rnd->Uniform(95));  // ' ' .. '~'
-  }
-  return Slice(*dst);
-}
-
-extern std::string RandomHumanReadableString(Random* rnd, int len) {
-  std::string ret;
-  ret.resize(len);
-  for (int i = 0; i < len; ++i) {
-    ret[i] = static_cast<char>('a' + rnd->Uniform(26));
-  }
-  return ret;
-}
-
 std::string RandomKey(Random* rnd, int len, RandomKeyType type) {
   // Make sure to generate a wide variety of characters so we
   // test the boundary conditions for short-key optimizations.
@@ -78,8 +63,7 @@ extern Slice CompressibleString(Random* rnd, double compressed_fraction,
                                 int len, std::string* dst) {
   int raw = static_cast<int>(len * compressed_fraction);
   if (raw < 1) raw = 1;
-  std::string raw_data;
-  RandomString(rnd, raw, &raw_data);
+  std::string raw_data = rnd->RandomString(raw);
 
   // Duplicate the random data until we have filled "len" bytes
   dst->clear();
@@ -453,51 +437,6 @@ void RandomInitCFOptions(ColumnFamilyOptions* cf_opt, DBOptions& db_options,
                               &cf_opt->compression_per_level, rnd);
 }
 
-Status DestroyDir(Env* env, const std::string& dir) {
-  Status s;
-  if (env->FileExists(dir).IsNotFound()) {
-    return s;
-  }
-  std::vector<std::string> files_in_dir;
-  s = env->GetChildren(dir, &files_in_dir);
-  if (s.ok()) {
-    for (auto& file_in_dir : files_in_dir) {
-      if (file_in_dir == "." || file_in_dir == "..") {
-        continue;
-      }
-      std::string path = dir + "/" + file_in_dir;
-      bool is_dir = false;
-      s = env->IsDirectory(path, &is_dir);
-      if (s.ok()) {
-        if (is_dir) {
-          s = DestroyDir(env, path);
-        } else {
-          s = env->DeleteFile(path);
-        }
-      }
-      if (!s.ok()) {
-        // IsDirectory, etc. might not report NotFound
-        if (s.IsNotFound() || env->FileExists(path).IsNotFound()) {
-          // Allow files to be deleted externally
-          s = Status::OK();
-        } else {
-          break;
-        }
-      }
-    }
-  }
-
-  if (s.ok()) {
-    s = env->DeleteDir(dir);
-    // DeleteDir might or might not report NotFound
-    if (!s.ok() && (s.IsNotFound() || env->FileExists(dir).IsNotFound())) {
-      // Allow to be deleted externally
-      s = Status::OK();
-    }
-  }
-  return s;
-}
-
 bool IsDirectIOSupported(Env* env, const std::string& dir) {
   EnvOptions env_options;
   env_options.use_mmap_writes = false;
@@ -531,22 +470,6 @@ size_t GetLinesCount(const std::string& fname, const std::string& pattern) {
   return count;
 }
 
-void SetupSyncPointsToMockDirectIO() {
-#if !defined(NDEBUG) && !defined(OS_MACOSX) && !defined(OS_WIN) && \
-    !defined(OS_SOLARIS) && !defined(OS_AIX) && !defined(OS_OPENBSD)
-  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
-      "NewWritableFile:O_DIRECT", [&](void* arg) {
-        int* val = static_cast<int*>(arg);
-        *val &= ~O_DIRECT;
-      });
-  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
-      "NewRandomAccessFile:O_DIRECT", [&](void* arg) {
-        int* val = static_cast<int*>(arg);
-        *val &= ~O_DIRECT;
-      });
-  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
-#endif
-}
 
 void CorruptFile(const std::string& fname, int offset, int bytes_to_corrupt) {
   struct stat sbuf;
diff --git a/test_util/testutil.h b/test_util/testutil.h
index f41a1dec8..4255a48f2 100644
--- a/test_util/testutil.h
+++ b/test_util/testutil.h
@@ -26,9 +26,9 @@
 #include "table/internal_iterator.h"
 #include "table/plain/plain_table_factory.h"
 #include "util/mutexlock.h"
-#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
+class Random;
 class SequentialFile;
 class SequentialFileReader;
 
@@ -37,12 +37,6 @@ namespace test {
 extern const uint32_t kDefaultFormatVersion;
 extern const uint32_t kLatestFormatVersion;
 
-// Store in *dst a random string of length "len" and return a Slice that
-// references the generated data.
-extern Slice RandomString(Random* rnd, int len, std::string* dst);
-
-extern std::string RandomHumanReadableString(Random* rnd, int len);
-
 // Return a random key with the specified length that may contain interesting
 // characters (e.g. \x00, \xff, etc.).
 enum RandomKeyType : char { RANDOM, LARGEST, SMALLEST, MIDDLE };
@@ -796,8 +790,6 @@ TableFactory* RandomTableFactory(Random* rnd, int pre_defined = -1);
 
 std::string RandomName(Random* rnd, const size_t len);
 
-Status DestroyDir(Env* env, const std::string& dir);
-
 bool IsDirectIOSupported(Env* env, const std::string& dir);
 
 // Return the number of lines where a given pattern was found in a file.
@@ -808,9 +800,6 @@ size_t GetLinesCount(const std::string& fname, const std::string& pattern);
 // Tries to set TEST_TMPDIR to a directory supporting direct IO.
 void ResetTmpDirForDirectIO();
 
-// Sets up sync points to mock direct IO instead of actually issuing direct IO
-// to the file system.
-void SetupSyncPointsToMockDirectIO();
 
 void CorruptFile(const std::string& fname, int offset, int bytes_to_corrupt);
 
diff --git a/test_util/testutil_test.cc b/test_util/testutil_test.cc
index d055af667..41f26e389 100644
--- a/test_util/testutil_test.cc
+++ b/test_util/testutil_test.cc
@@ -5,6 +5,7 @@
 
 #include "test_util/testutil.h"
 
+#include "file/file_util.h"
 #include "port/port.h"
 #include "port/stack_trace.h"
 #include "test_util/testharness.h"
@@ -28,7 +29,7 @@ TEST(TestUtil, DestroyDirRecursively) {
   ASSERT_OK(env->CreateDir(test_dir + "/dir"));
   CreateFile(env, test_dir + "/dir/file");
 
-  ASSERT_OK(test::DestroyDir(env, test_dir));
+  ASSERT_OK(DestroyDir(env, test_dir));
   auto s = env->FileExists(test_dir);
   ASSERT_TRUE(s.IsNotFound());
 }
diff --git a/tools/db_repl_stress.cc b/tools/db_repl_stress.cc
index 717f5d3d8..794ac1530 100644
--- a/tools/db_repl_stress.cc
+++ b/tools/db_repl_stress.cc
@@ -37,20 +37,14 @@ struct DataPumpThread {
   DB* db;  // Assumption DB is Open'ed already.
 };
 
-static std::string RandomString(Random* rnd, int len) {
-  std::string r;
-  test::RandomString(rnd, len, &r);
-  return r;
-}
-
 static void DataPumpThreadBody(void* arg) {
   DataPumpThread* t = reinterpret_cast<DataPumpThread*>(arg);
   DB* db = t->db;
   Random rnd(301);
   size_t i = 0;
   while (i++ < t->no_records) {
-    if (!db->Put(WriteOptions(), Slice(RandomString(&rnd, 500)),
-                 Slice(RandomString(&rnd, 500)))
+    if (!db->Put(WriteOptions(), Slice(rnd.RandomString(500)),
+                 Slice(rnd.RandomString(500)))
              .ok()) {
       fprintf(stderr, "Error in put\n");
       exit(1);
diff --git a/tools/ldb_cmd_test.cc b/tools/ldb_cmd_test.cc
index e8aa387a2..fce26aabb 100644
--- a/tools/ldb_cmd_test.cc
+++ b/tools/ldb_cmd_test.cc
@@ -6,6 +6,7 @@
 #ifndef ROCKSDB_LITE
 
 #include "rocksdb/utilities/ldb_cmd.h"
+
 #include "db/version_edit.h"
 #include "db/version_set.h"
 #include "env/composite_env_wrapper.h"
@@ -16,6 +17,7 @@
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
 #include "util/file_checksum_helper.h"
+#include "util/random.h"
 
 using std::string;
 using std::vector;
@@ -284,32 +286,28 @@ TEST_F(LdbCmdTest, DumpFileChecksumNoChecksum) {
   for (int i = 0; i < 200; i++) {
     char buf[16];
     snprintf(buf, sizeof(buf), "%08d", i);
-    std::string v;
-    test::RandomString(&rnd, 100, &v);
+    std::string v = rnd.RandomString(100);
     ASSERT_OK(db->Put(wopts, buf, v));
   }
   ASSERT_OK(db->Flush(fopts));
   for (int i = 100; i < 300; i++) {
     char buf[16];
     snprintf(buf, sizeof(buf), "%08d", i);
-    std::string v;
-    test::RandomString(&rnd, 100, &v);
+    std::string v = rnd.RandomString(100);
     ASSERT_OK(db->Put(wopts, buf, v));
   }
   ASSERT_OK(db->Flush(fopts));
   for (int i = 200; i < 400; i++) {
     char buf[16];
     snprintf(buf, sizeof(buf), "%08d", i);
-    std::string v;
-    test::RandomString(&rnd, 100, &v);
+    std::string v = rnd.RandomString(100);
     ASSERT_OK(db->Put(wopts, buf, v));
   }
   ASSERT_OK(db->Flush(fopts));
   for (int i = 300; i < 400; i++) {
     char buf[16];
     snprintf(buf, sizeof(buf), "%08d", i);
-    std::string v;
-    test::RandomString(&rnd, 100, &v);
+    std::string v = rnd.RandomString(100);
     ASSERT_OK(db->Put(wopts, buf, v));
   }
   ASSERT_OK(db->Flush(fopts));
@@ -369,32 +367,28 @@ TEST_F(LdbCmdTest, DumpFileChecksumCRC32) {
   for (int i = 0; i < 100; i++) {
     char buf[16];
     snprintf(buf, sizeof(buf), "%08d", i);
-    std::string v;
-    test::RandomString(&rnd, 100, &v);
+    std::string v = rnd.RandomString(100);
     ASSERT_OK(db->Put(wopts, buf, v));
   }
   ASSERT_OK(db->Flush(fopts));
   for (int i = 50; i < 150; i++) {
     char buf[16];
     snprintf(buf, sizeof(buf), "%08d", i);
-    std::string v;
-    test::RandomString(&rnd, 100, &v);
+    std::string v = rnd.RandomString(100);
     ASSERT_OK(db->Put(wopts, buf, v));
   }
   ASSERT_OK(db->Flush(fopts));
   for (int i = 100; i < 200; i++) {
     char buf[16];
     snprintf(buf, sizeof(buf), "%08d", i);
-    std::string v;
-    test::RandomString(&rnd, 100, &v);
+    std::string v = rnd.RandomString(100);
     ASSERT_OK(db->Put(wopts, buf, v));
   }
   ASSERT_OK(db->Flush(fopts));
   for (int i = 150; i < 250; i++) {
     char buf[16];
     snprintf(buf, sizeof(buf), "%08d", i);
-    std::string v;
-    test::RandomString(&rnd, 100, &v);
+    std::string v = rnd.RandomString(100);
     ASSERT_OK(db->Put(wopts, buf, v));
   }
   ASSERT_OK(db->Flush(fopts));
diff --git a/util/file_reader_writer_test.cc b/util/file_reader_writer_test.cc
index f37bd5931..0f1cc499b 100644
--- a/util/file_reader_writer_test.cc
+++ b/util/file_reader_writer_test.cc
@@ -166,8 +166,7 @@ TEST_F(WritableFileWriterTest, IncrementalBuffer) {
     std::string target;
     for (int i = 0; i < 20; i++) {
       uint32_t num = r.Skewed(16) * 100 + r.Uniform(100);
-      std::string random_string;
-      test::RandomString(&r, num, &random_string);
+      std::string random_string = r.RandomString(num);
       writer->Append(Slice(random_string.c_str(), num));
       target.append(random_string.c_str(), num);
 
@@ -288,8 +287,7 @@ TEST_P(ReadaheadRandomAccessFileTest, SourceStrLenGreaterThanReadaheadSize) {
   for (int k = 0; k < 100; ++k) {
     size_t strLen = k * GetReadaheadSize() +
                     rng.Uniform(static_cast<int>(GetReadaheadSize()));
-    std::string str =
-        test::RandomHumanReadableString(&rng, static_cast<int>(strLen));
+    std::string str = rng.HumanReadableString(static_cast<int>(strLen));
     ResetSourceStr(str);
     for (int test = 1; test <= 100; ++test) {
       size_t offset = rng.Uniform(static_cast<int>(strLen));
@@ -304,8 +302,7 @@ TEST_P(ReadaheadRandomAccessFileTest, ReadExceedsReadaheadSize) {
   Random rng(7);
   size_t strLen = 4 * GetReadaheadSize() +
                   rng.Uniform(static_cast<int>(GetReadaheadSize()));
-  std::string str =
-      test::RandomHumanReadableString(&rng, static_cast<int>(strLen));
+  std::string str = rng.HumanReadableString(static_cast<int>(strLen));
   ResetSourceStr(str);
   for (int test = 1; test <= 100; ++test) {
     size_t offset = rng.Uniform(static_cast<int>(strLen));
@@ -383,8 +380,7 @@ TEST_P(ReadaheadSequentialFileTest, SourceStrLenGreaterThanReadaheadSize) {
     for (int k = 0; k < 100; ++k) {
       size_t strLen = k * GetReadaheadSize() +
                       rng.Uniform(static_cast<int>(GetReadaheadSize()));
-      std::string str =
-          test::RandomHumanReadableString(&rng, static_cast<int>(strLen));
+      std::string str = rng.HumanReadableString(static_cast<int>(strLen));
       ResetSourceStr(str);
       size_t offset = 0;
       for (int test = 1; test <= 100; ++test) {
@@ -406,8 +402,7 @@ TEST_P(ReadaheadSequentialFileTest, ReadExceedsReadaheadSize) {
     for (int k = 0; k < 100; ++k) {
       size_t strLen = k * GetReadaheadSize() +
                       rng.Uniform(static_cast<int>(GetReadaheadSize()));
-      std::string str =
-          test::RandomHumanReadableString(&rng, static_cast<int>(strLen));
+      std::string str = rng.HumanReadableString(static_cast<int>(strLen));
       ResetSourceStr(str);
       size_t offset = 0;
       for (int test = 1; test <= 100; ++test) {
diff --git a/util/random.cc b/util/random.cc
index 38c36defd..68624ad43 100644
--- a/util/random.cc
+++ b/util/random.cc
@@ -35,4 +35,22 @@ Random* Random::GetTLSInstance() {
   return rv;
 }
 
+std::string Random::HumanReadableString(int len) {
+  std::string ret;
+  ret.resize(len);
+  for (int i = 0; i < len; ++i) {
+    ret[i] = static_cast<char>('a' + Uniform(26));
+  }
+  return ret;
+}
+
+std::string Random::RandomString(int len) {
+  std::string ret;
+  ret.resize(len);
+  for (int i = 0; i < len; i++) {
+    ret[i] = static_cast<char>(' ' + Uniform(95));  // ' ' .. '~'
+  }
+  return ret;
+}
+
 }  // namespace ROCKSDB_NAMESPACE
diff --git a/util/random.h b/util/random.h
index 246d6c2ff..5f6eaf51e 100644
--- a/util/random.h
+++ b/util/random.h
@@ -86,6 +86,12 @@ class Random {
     return Uniform(1 << Uniform(max_log + 1));
   }
 
+  // Returns a random string of length "len"
+  std::string RandomString(int len);
+
+  // Generates a random string of len bytes using human-readable characters
+  std::string HumanReadableString(int len);
+
   // Returns a Random instance for use by the current thread without
   // additional locking
   static Random* GetTLSInstance();
diff --git a/utilities/backupable/backupable_db_test.cc b/utilities/backupable/backupable_db_test.cc
index 126f63b79..9e8aeb176 100644
--- a/utilities/backupable/backupable_db_test.cc
+++ b/utilities/backupable/backupable_db_test.cc
@@ -446,8 +446,7 @@ class FileManager : public EnvWrapper {
     }
 
     for (uint64_t i = 0; i < bytes_to_corrupt; ++i) {
-      std::string tmp;
-      test::RandomString(&rnd_, 1, &tmp);
+      std::string tmp = rnd_.RandomString(1);
       file_contents[rnd_.Next() % file_contents.size()] = tmp[0];
     }
     return WriteToFile(fname, file_contents);
diff --git a/utilities/blob_db/blob_db_test.cc b/utilities/blob_db/blob_db_test.cc
index 6ba672ed9..95533cd6a 100644
--- a/utilities/blob_db/blob_db_test.cc
+++ b/utilities/blob_db/blob_db_test.cc
@@ -5,6 +5,8 @@
 
 #ifndef ROCKSDB_LITE
 
+#include "utilities/blob_db/blob_db.h"
+
 #include <algorithm>
 #include <chrono>
 #include <cstdlib>
@@ -22,14 +24,13 @@
 #include "file/sst_file_manager_impl.h"
 #include "port/port.h"
 #include "rocksdb/utilities/debug.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/sync_point.h"
 #include "test_util/testharness.h"
 #include "util/cast_util.h"
 #include "util/random.h"
 #include "util/string_util.h"
-#include "utilities/blob_db/blob_db.h"
 #include "utilities/blob_db/blob_db_impl.h"
+#include "utilities/fault_injection_env.h"
 
 namespace ROCKSDB_NAMESPACE {
 namespace blob_db {
@@ -142,7 +143,7 @@ class BlobDBTest : public testing::Test {
   void PutRandomWithTTL(const std::string &key, uint64_t ttl, Random *rnd,
                         std::map<std::string, std::string> *data = nullptr) {
     int len = rnd->Next() % kMaxBlobSize + 1;
-    std::string value = test::RandomHumanReadableString(rnd, len);
+    std::string value = rnd->HumanReadableString(len);
     ASSERT_OK(
         blob_db_->PutWithTTL(WriteOptions(), Slice(key), Slice(value), ttl));
     if (data != nullptr) {
@@ -153,7 +154,7 @@ class BlobDBTest : public testing::Test {
   void PutRandomUntil(const std::string &key, uint64_t expiration, Random *rnd,
                       std::map<std::string, std::string> *data = nullptr) {
     int len = rnd->Next() % kMaxBlobSize + 1;
-    std::string value = test::RandomHumanReadableString(rnd, len);
+    std::string value = rnd->HumanReadableString(len);
     ASSERT_OK(blob_db_->PutUntil(WriteOptions(), Slice(key), Slice(value),
                                  expiration));
     if (data != nullptr) {
@@ -169,7 +170,7 @@ class BlobDBTest : public testing::Test {
   void PutRandom(DB *db, const std::string &key, Random *rnd,
                  std::map<std::string, std::string> *data = nullptr) {
     int len = rnd->Next() % kMaxBlobSize + 1;
-    std::string value = test::RandomHumanReadableString(rnd, len);
+    std::string value = rnd->HumanReadableString(len);
     ASSERT_OK(db->Put(WriteOptions(), Slice(key), Slice(value)));
     if (data != nullptr) {
       (*data)[key] = value;
@@ -180,7 +181,7 @@ class BlobDBTest : public testing::Test {
       const std::string &key, Random *rnd, WriteBatch *batch,
       std::map<std::string, std::string> *data = nullptr) {
     int len = rnd->Next() % kMaxBlobSize + 1;
-    std::string value = test::RandomHumanReadableString(rnd, len);
+    std::string value = rnd->HumanReadableString(len);
     ASSERT_OK(batch->Put(key, value));
     if (data != nullptr) {
       (*data)[key] = value;
@@ -1079,7 +1080,7 @@ TEST_F(BlobDBTest, InlineSmallValues) {
     uint64_t expiration = rnd.Next() % kMaxExpiration;
     int len = is_small_value ? 50 : 200;
     std::string key = "key" + ToString(i);
-    std::string value = test::RandomHumanReadableString(&rnd, len);
+    std::string value = rnd.HumanReadableString(len);
     std::string blob_index;
     data[key] = value;
     SequenceNumber sequence = blob_db_->GetLatestSequenceNumber() + 1;
@@ -1186,8 +1187,7 @@ TEST_F(BlobDBTest, UserCompactionFilter) {
       oss << "key" << std::setw(4) << std::setfill('0') << i;
 
       const std::string key(oss.str());
-      const std::string value(
-          test::RandomHumanReadableString(&rnd, (int)value_size));
+      const std::string value = rnd.HumanReadableString((int)value_size);
       const SequenceNumber sequence = blob_db_->GetLatestSequenceNumber() + 1;
 
       ASSERT_OK(Put(key, value));
@@ -1264,8 +1264,7 @@ TEST_F(BlobDBTest, UserCompactionFilter_BlobIOError) {
       oss << "key" << std::setw(4) << std::setfill('0') << i;
 
       const std::string key(oss.str());
-      const std::string value(
-          test::RandomHumanReadableString(&rnd, kValueSize));
+      const std::string value = rnd.HumanReadableString(kValueSize);
       const SequenceNumber sequence = blob_db_->GetLatestSequenceNumber() + 1;
 
       ASSERT_OK(Put(key, value));
@@ -1319,7 +1318,7 @@ TEST_F(BlobDBTest, FilterExpiredBlobIndex) {
     uint64_t expiration = rnd.Next() % kMaxExpiration;
     int len = is_small_value ? 10 : 200;
     std::string key = "key" + ToString(rnd.Next() % kNumKeys);
-    std::string value = test::RandomHumanReadableString(&rnd, len);
+    std::string value = rnd.HumanReadableString(len);
     if (!has_ttl) {
       if (is_small_value) {
         std::string blob_entry;
@@ -1440,7 +1439,7 @@ TEST_F(BlobDBTest, FilterForFIFOEviction) {
   // Insert some small values that will be inlined.
   for (int i = 0; i < 1000; i++) {
     std::string key = "key" + ToString(i);
-    std::string value = test::RandomHumanReadableString(&rnd, 50);
+    std::string value = rnd.HumanReadableString(50);
     uint64_t ttl = rnd.Next() % 120 + 1;
     ASSERT_OK(PutWithTTL(key, value, ttl, &data));
     if (ttl >= 60) {
@@ -1548,8 +1547,7 @@ TEST_F(BlobDBTest, GarbageCollection) {
     oss << "key" << std::setw(4) << std::setfill('0') << i;
 
     const std::string key(oss.str());
-    const std::string value(
-        test::RandomHumanReadableString(&rnd, kLargeValueSize));
+    const std::string value = rnd.HumanReadableString(kLargeValueSize);
     const SequenceNumber sequence = blob_db_->GetLatestSequenceNumber() + 1;
 
     ASSERT_OK(Put(key, value));
@@ -1566,8 +1564,7 @@ TEST_F(BlobDBTest, GarbageCollection) {
   // First, add a large TTL value will be written to its own TTL blob file.
   {
     const std::string key("key2000");
-    const std::string value(
-        test::RandomHumanReadableString(&rnd, kLargeValueSize));
+    const std::string value = rnd.HumanReadableString(kLargeValueSize);
     const SequenceNumber sequence = blob_db_->GetLatestSequenceNumber() + 1;
 
     ASSERT_OK(PutUntil(key, value, kExpiration));
@@ -1583,8 +1580,7 @@ TEST_F(BlobDBTest, GarbageCollection) {
   // Now add a small TTL value (which will be inlined).
   {
     const std::string key("key3000");
-    const std::string value(
-        test::RandomHumanReadableString(&rnd, kSmallValueSize));
+    const std::string value = rnd.HumanReadableString(kSmallValueSize);
     const SequenceNumber sequence = blob_db_->GetLatestSequenceNumber() + 1;
 
     ASSERT_OK(PutUntil(key, value, kExpiration));
@@ -1600,8 +1596,7 @@ TEST_F(BlobDBTest, GarbageCollection) {
   // value).
   {
     const std::string key("key4000");
-    const std::string value(
-        test::RandomHumanReadableString(&rnd, kSmallValueSize));
+    const std::string value = rnd.HumanReadableString(kSmallValueSize);
     const SequenceNumber sequence = blob_db_->GetLatestSequenceNumber() + 1;
 
     ASSERT_OK(Put(key, value));
diff --git a/utilities/checkpoint/checkpoint_test.cc b/utilities/checkpoint/checkpoint_test.cc
index eb6b0f12b..823a169bd 100644
--- a/utilities/checkpoint/checkpoint_test.cc
+++ b/utilities/checkpoint/checkpoint_test.cc
@@ -9,6 +9,7 @@
 
 // Syncpoint prevents us building and running tests in release
 #ifndef ROCKSDB_LITE
+#include "rocksdb/utilities/checkpoint.h"
 
 #ifndef OS_WIN
 #include <unistd.h>
@@ -16,17 +17,18 @@
 #include <iostream>
 #include <thread>
 #include <utility>
+
 #include "db/db_impl/db_impl.h"
+#include "file/file_util.h"
 #include "port/port.h"
 #include "port/stack_trace.h"
 #include "rocksdb/db.h"
 #include "rocksdb/env.h"
-#include "rocksdb/utilities/checkpoint.h"
 #include "rocksdb/utilities/transaction_db.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/sync_point.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
+#include "utilities/fault_injection_env.h"
 
 namespace ROCKSDB_NAMESPACE {
 class CheckpointTest : public testing::Test {
@@ -69,7 +71,7 @@ class CheckpointTest : public testing::Test {
     env_->DeleteDir(snapshot_tmp_name);
     Reopen(options);
     export_path_ = test::PerThreadDBPath("/export");
-    test::DestroyDir(env_, export_path_);
+    DestroyDir(env_, export_path_);
     cfh_reverse_comp_ = nullptr;
     metadata_ = nullptr;
   }
@@ -94,7 +96,7 @@ class CheckpointTest : public testing::Test {
     options.db_paths.emplace_back(dbname_ + "_4", 0);
     EXPECT_OK(DestroyDB(dbname_, options));
     EXPECT_OK(DestroyDB(snapshot_name_, options));
-    test::DestroyDir(env_, export_path_);
+    DestroyDir(env_, export_path_);
   }
 
   // Return the current option configuration.
@@ -347,7 +349,7 @@ TEST_F(CheckpointTest, ExportColumnFamilyWithLinks) {
                                              export_path_, &metadata_));
     verify_files_exported(*metadata_, 1);
     ASSERT_EQ(metadata_->db_comparator_name, options.comparator->Name());
-    test::DestroyDir(env_, export_path_);
+    DestroyDir(env_, export_path_);
     delete metadata_;
     metadata_ = nullptr;
 
@@ -358,7 +360,7 @@ TEST_F(CheckpointTest, ExportColumnFamilyWithLinks) {
                                              export_path_, &metadata_));
     verify_files_exported(*metadata_, 2);
     ASSERT_EQ(metadata_->db_comparator_name, options.comparator->Name());
-    test::DestroyDir(env_, export_path_);
+    DestroyDir(env_, export_path_);
     delete metadata_;
     metadata_ = nullptr;
     delete checkpoint;
@@ -404,7 +406,7 @@ TEST_F(CheckpointTest, ExportColumnFamilyNegativeTest) {
   ASSERT_EQ(checkpoint->ExportColumnFamily(db_->DefaultColumnFamily(),
                                            export_path_, &metadata_),
             Status::InvalidArgument("Specified export_dir exists"));
-  test::DestroyDir(env_, export_path_);
+  DestroyDir(env_, export_path_);
 
   // Export with invalid directory specification
   export_path_ = "";
diff --git a/test_util/fault_injection_test_env.cc b/utilities/fault_injection_env.cc
similarity index 99%
rename from test_util/fault_injection_test_env.cc
rename to utilities/fault_injection_env.cc
index d9c2167b4..06ce6b352 100644
--- a/test_util/fault_injection_test_env.cc
+++ b/utilities/fault_injection_env.cc
@@ -11,10 +11,12 @@
 // the last "sync". It then checks for data loss errors by purposely dropping
 // file data (or entire files) not protected by a "sync".
 
-#include "test_util/fault_injection_test_env.h"
+#include "utilities/fault_injection_env.h"
+
 #include <functional>
 #include <utility>
 
+#include "util/random.h"
 namespace ROCKSDB_NAMESPACE {
 
 // Assume a filename, and not a directory name like "/foo/bar/"
diff --git a/test_util/fault_injection_test_env.h b/utilities/fault_injection_env.h
similarity index 98%
rename from test_util/fault_injection_test_env.h
rename to utilities/fault_injection_env.h
index 9cc33a8d3..0de73cbe2 100644
--- a/test_util/fault_injection_test_env.h
+++ b/utilities/fault_injection_env.h
@@ -17,16 +17,12 @@
 #include <set>
 #include <string>
 
-#include "db/version_set.h"
-#include "env/mock_env.h"
 #include "file/filename.h"
-#include "rocksdb/db.h"
 #include "rocksdb/env.h"
 #include "util/mutexlock.h"
-#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
-
+class Random;
 class TestWritableFile;
 class FaultInjectionTestEnv;
 
diff --git a/test_util/fault_injection_test_fs.cc b/utilities/fault_injection_fs.cc
similarity index 99%
rename from test_util/fault_injection_test_fs.cc
rename to utilities/fault_injection_fs.cc
index f08ab5ef9..5ee901523 100644
--- a/test_util/fault_injection_test_fs.cc
+++ b/utilities/fault_injection_fs.cc
@@ -14,11 +14,15 @@
 // FileSystem related operations, by specify the "IOStatus Error", a specific
 // error can be returned when file system is not activated.
 
-#include "test_util/fault_injection_test_fs.h"
+#include "utilities/fault_injection_fs.h"
+
 #include <functional>
 #include <utility>
+
+#include "env/composite_env_wrapper.h"
 #include "port/lang.h"
 #include "port/stack_trace.h"
+#include "util/random.h"
 
 namespace ROCKSDB_NAMESPACE {
 
@@ -501,8 +505,7 @@ IOStatus FaultInjectionTestFS::InjectError(ErrorOperation op,
               // The randomly generated string could be identical to the
               // original one, so retry
               do {
-                str = DBTestBase::RandomString(&ctx->rand,
-                                    static_cast<int>(len));
+                str = ctx->rand.RandomString(static_cast<int>(len));
               } while (str == std::string(scratch + offset, len));
               memcpy(scratch + offset, str.data(), len);
               break;
diff --git a/test_util/fault_injection_test_fs.h b/utilities/fault_injection_fs.h
similarity index 99%
rename from test_util/fault_injection_test_fs.h
rename to utilities/fault_injection_fs.h
index 1ac0d6269..07b7efdad 100644
--- a/test_util/fault_injection_test_fs.h
+++ b/utilities/fault_injection_fs.h
@@ -21,15 +21,11 @@
 #include <set>
 #include <string>
 
-#include "db/db_test_util.h"
-#include "db/version_set.h"
-#include "env/mock_env.h"
 #include "file/filename.h"
 #include "include/rocksdb/file_system.h"
-#include "rocksdb/db.h"
-#include "rocksdb/env.h"
 #include "util/mutexlock.h"
 #include "util/random.h"
+#include "util/thread_local.h"
 
 namespace ROCKSDB_NAMESPACE {
 
diff --git a/utilities/memory/memory_test.cc b/utilities/memory/memory_test.cc
index 9e253df44..914900362 100644
--- a/utilities/memory/memory_test.cc
+++ b/utilities/memory/memory_test.cc
@@ -13,6 +13,7 @@
 #include "table/block_based/block_based_table_factory.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
+#include "util/random.h"
 #include "util/string_util.h"
 
 namespace ROCKSDB_NAMESPACE {
@@ -25,12 +26,6 @@ class MemoryTest : public testing::Test {
 
   std::string GetDBName(int id) { return kDbDir + "db_" + ToString(id); }
 
-  std::string RandomString(int len) {
-    std::string r;
-    test::RandomString(&rnd_, len, &r);
-    return r;
-  }
-
   void UpdateUsagesHistory(const std::vector<DB*>& dbs) {
     std::map<MemoryUtil::UsageType, uint64_t> usage_by_type;
     ASSERT_OK(GetApproximateMemoryUsageByType(dbs, &usage_by_type));
@@ -122,9 +117,9 @@ TEST_F(MemoryTest, SharedBlockCacheTotal) {
   for (int p = 0; p < opt.min_write_buffer_number_to_merge / 2; ++p) {
     for (int i = 0; i < kNumDBs; ++i) {
       for (int j = 0; j < 100; ++j) {
-        keys_by_db[i].emplace_back(RandomString(kKeySize));
+        keys_by_db[i].emplace_back(rnd_.RandomString(kKeySize));
         dbs[i]->Put(WriteOptions(), keys_by_db[i].back(),
-                    RandomString(kValueSize));
+                    rnd_.RandomString(kValueSize));
       }
       dbs[i]->Flush(FlushOptions());
     }
@@ -181,8 +176,8 @@ TEST_F(MemoryTest, MemTableAndTableReadersTotal) {
   for (int p = 0; p < opt.min_write_buffer_number_to_merge / 2; ++p) {
     for (int i = 0; i < kNumDBs; ++i) {
       for (auto* handle : vec_handles[i]) {
-        dbs[i]->Put(WriteOptions(), handle, RandomString(kKeySize),
-                    RandomString(kValueSize));
+        dbs[i]->Put(WriteOptions(), handle, rnd_.RandomString(kKeySize),
+                    rnd_.RandomString(kValueSize));
         UpdateUsagesHistory(dbs);
       }
     }
@@ -208,7 +203,7 @@ TEST_F(MemoryTest, MemTableAndTableReadersTotal) {
 
     for (int j = 0; j < 100; ++j) {
       std::string value;
-      dbs[i]->Get(ReadOptions(), RandomString(kKeySize), &value);
+      dbs[i]->Get(ReadOptions(), rnd_.RandomString(kKeySize), &value);
     }
 
     UpdateUsagesHistory(dbs);
diff --git a/utilities/option_change_migration/option_change_migration_test.cc b/utilities/option_change_migration/option_change_migration_test.cc
index 5bc883ff7..a03cabac9 100644
--- a/utilities/option_change_migration/option_change_migration_test.cc
+++ b/utilities/option_change_migration/option_change_migration_test.cc
@@ -8,9 +8,13 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 
 #include "rocksdb/utilities/option_change_migration.h"
+
 #include <set>
+
 #include "db/db_test_util.h"
 #include "port/stack_trace.h"
+#include "util/random.h"
+
 namespace ROCKSDB_NAMESPACE {
 
 class DBOptionChangeMigrationTests
@@ -200,7 +204,7 @@ TEST_P(DBOptionChangeMigrationTests, Migrate3) {
   Random rnd(301);
   for (int num = 0; num < 20; num++) {
     for (int i = 0; i < 50; i++) {
-      ASSERT_OK(Put(Key(num * 100 + i), RandomString(&rnd, 900)));
+      ASSERT_OK(Put(Key(num * 100 + i), rnd.RandomString(900)));
     }
     Flush();
     dbfull()->TEST_WaitForCompact();
@@ -274,7 +278,7 @@ TEST_P(DBOptionChangeMigrationTests, Migrate4) {
   Random rnd(301);
   for (int num = 0; num < 20; num++) {
     for (int i = 0; i < 50; i++) {
-      ASSERT_OK(Put(Key(num * 100 + i), RandomString(&rnd, 900)));
+      ASSERT_OK(Put(Key(num * 100 + i), rnd.RandomString(900)));
     }
     Flush();
     dbfull()->TEST_WaitForCompact();
@@ -370,7 +374,7 @@ TEST_F(DBOptionChangeMigrationTest, CompactedSrcToUniversal) {
   Random rnd(301);
   for (int num = 0; num < 20; num++) {
     for (int i = 0; i < 50; i++) {
-      ASSERT_OK(Put(Key(num * 100 + i), RandomString(&rnd, 900)));
+      ASSERT_OK(Put(Key(num * 100 + i), rnd.RandomString(900)));
     }
   }
   Flush();
diff --git a/utilities/persistent_cache/persistent_cache_test.h b/utilities/persistent_cache/persistent_cache_test.h
index 47611ecd3..394c64964 100644
--- a/utilities/persistent_cache/persistent_cache_test.h
+++ b/utilities/persistent_cache/persistent_cache_test.h
@@ -24,6 +24,7 @@
 #include "rocksdb/cache.h"
 #include "table/block_based/block_builder.h"
 #include "test_util/testharness.h"
+#include "util/random.h"
 #include "utilities/persistent_cache/volatile_tier_impl.h"
 
 namespace ROCKSDB_NAMESPACE {
@@ -255,7 +256,7 @@ class PersistentCacheDBTest : public DBTestBase {
     std::string str;
     for (int i = 0; i < num_iter; i++) {
       if (i % 4 == 0) {  // high compression ratio
-        str = RandomString(&rnd, 1000);
+        str = rnd.RandomString(1000);
       }
       values->push_back(str);
       ASSERT_OK(Put(1, Key(i), (*values)[i]));
diff --git a/utilities/transactions/transaction_lock_mgr_test.cc b/utilities/transactions/transaction_lock_mgr_test.cc
index f42caed86..e67b453ca 100644
--- a/utilities/transactions/transaction_lock_mgr_test.cc
+++ b/utilities/transactions/transaction_lock_mgr_test.cc
@@ -6,6 +6,8 @@
 #ifndef ROCKSDB_LITE
 
 #include "utilities/transactions/transaction_lock_mgr.h"
+
+#include "file/file_util.h"
 #include "port/port.h"
 #include "port/stack_trace.h"
 #include "rocksdb/utilities/transaction_db.h"
@@ -36,7 +38,7 @@ class TransactionLockMgrTest : public testing::Test {
 
   void TearDown() override {
     delete db_;
-    EXPECT_OK(test::DestroyDir(env_, db_dir_));
+    EXPECT_OK(DestroyDir(env_, db_dir_));
   }
 
   PessimisticTransaction* NewTxn(
diff --git a/utilities/transactions/transaction_test.cc b/utilities/transactions/transaction_test.cc
index f153b9a14..30058a757 100644
--- a/utilities/transactions/transaction_test.cc
+++ b/utilities/transactions/transaction_test.cc
@@ -13,25 +13,24 @@
 #include <thread>
 
 #include "db/db_impl/db_impl.h"
+#include "port/port.h"
 #include "rocksdb/db.h"
 #include "rocksdb/options.h"
 #include "rocksdb/perf_context.h"
 #include "rocksdb/utilities/transaction.h"
 #include "rocksdb/utilities/transaction_db.h"
 #include "table/mock_table.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/sync_point.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
 #include "test_util/transaction_test_util.h"
 #include "util/random.h"
 #include "util/string_util.h"
+#include "utilities/fault_injection_env.h"
 #include "utilities/merge_operators.h"
 #include "utilities/merge_operators/string_append/stringappend.h"
 #include "utilities/transactions/pessimistic_transaction_db.h"
 
-#include "port/port.h"
-
 using std::string;
 
 namespace ROCKSDB_NAMESPACE {
diff --git a/utilities/transactions/transaction_test.h b/utilities/transactions/transaction_test.h
index 4fc0422c7..2f3ab2ba8 100644
--- a/utilities/transactions/transaction_test.h
+++ b/utilities/transactions/transaction_test.h
@@ -12,25 +12,24 @@
 #include <thread>
 
 #include "db/db_impl/db_impl.h"
+#include "port/port.h"
 #include "rocksdb/db.h"
 #include "rocksdb/options.h"
 #include "rocksdb/utilities/transaction.h"
 #include "rocksdb/utilities/transaction_db.h"
 #include "table/mock_table.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/sync_point.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
 #include "test_util/transaction_test_util.h"
 #include "util/random.h"
 #include "util/string_util.h"
+#include "utilities/fault_injection_env.h"
 #include "utilities/merge_operators.h"
 #include "utilities/merge_operators/string_append/stringappend.h"
 #include "utilities/transactions/pessimistic_transaction_db.h"
 #include "utilities/transactions/write_unprepared_txn_db.h"
 
-#include "port/port.h"
-
 namespace ROCKSDB_NAMESPACE {
 
 // Return true if the ith bit is set in combination represented by comb
diff --git a/utilities/transactions/write_prepared_transaction_test.cc b/utilities/transactions/write_prepared_transaction_test.cc
index 8adca08e3..a999c71d4 100644
--- a/utilities/transactions/write_prepared_transaction_test.cc
+++ b/utilities/transactions/write_prepared_transaction_test.cc
@@ -5,8 +5,6 @@
 
 #ifndef ROCKSDB_LITE
 
-#include "utilities/transactions/transaction_test.h"
-
 #include <algorithm>
 #include <atomic>
 #include <cinttypes>
@@ -16,6 +14,7 @@
 
 #include "db/db_impl/db_impl.h"
 #include "db/dbformat.h"
+#include "port/port.h"
 #include "rocksdb/db.h"
 #include "rocksdb/options.h"
 #include "rocksdb/types.h"
@@ -23,7 +22,6 @@
 #include "rocksdb/utilities/transaction.h"
 #include "rocksdb/utilities/transaction_db.h"
 #include "table/mock_table.h"
-#include "test_util/fault_injection_test_env.h"
 #include "test_util/sync_point.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
@@ -31,13 +29,13 @@
 #include "util/mutexlock.h"
 #include "util/random.h"
 #include "util/string_util.h"
+#include "utilities/fault_injection_env.h"
 #include "utilities/merge_operators.h"
 #include "utilities/merge_operators/string_append/stringappend.h"
 #include "utilities/transactions/pessimistic_transaction_db.h"
+#include "utilities/transactions/transaction_test.h"
 #include "utilities/transactions/write_prepared_txn_db.h"
 
-#include "port/port.h"
-
 using std::string;
 
 namespace ROCKSDB_NAMESPACE {
@@ -277,8 +275,8 @@ TEST(WriteBatchWithIndex, SubBatchCnt) {
       for (size_t k = 0; k < 10; k++) {  // 10 key per batch
         size_t ki = static_cast<size_t>(rnd.Uniform(TOTAL_KEYS));
         Slice key = Slice(keys[ki]);
-        std::string buffer;
-        Slice value = Slice(test::RandomString(&rnd, 16, &buffer));
+        std::string tmp = rnd.RandomString(16);
+        Slice value = Slice(tmp);
         rndbatch.Put(key, value);
       }
       SubBatchCounter batch_counter(comparators);