diff --git a/build_tools/build_detect_platform b/build_tools/build_detect_platform
index 8e92b9b6b..29d94f01d 100755
--- a/build_tools/build_detect_platform
+++ b/build_tools/build_detect_platform
@@ -175,7 +175,7 @@ PRUNE_TEST="-name *test*.cc -prune"
 PRUNE_BENCH="-name *bench*.cc -prune"
 PRUNE_MOCK="-name *mock*.cc -prune"
 PORTABLE_FILES=`cd "$ROCKSDB_ROOT"; find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o $PRUNE_MOCK -o -name '*.cc' -print | sort | tr "\n" " "`
-MOCK_SOURCES=`cd "$ROCKSDB_ROOT"; find $DIRS -name '*mock*.cc' -print | sort | tr "\n" " "`
+MOCK_SOURCES=`cd "$ROCKSDB_ROOT"; find $DIRS -name '*mock*.cc' -print | grep -v "test" | sort | tr "\n" " "`
 set +f # re-enable globbing
 
 # The sources consist of the portable files, plus the platform-specific port