tests: Copy fixtures into unique temporary directories

If a test is going to do a potentially destructive operation, instead of mutating shared fixtures, it should copy the fixture to its own unique directory and then mutate that copy (doesn't this sound like Rust's borrowing and ownership rules?! ^.^)
7 years ago · ccd8edbae1
parent cd572f9ee8
commit ccd8edbae1
9 changed files with 210 additions and 149 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@ -16,7 +16,7 @@ dependencies = [

 [[package]]
 name = "atty"
-version = "0.2.10"
+version = "0.2.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "libc 0.2.42 (registry+https://github.com/rust-lang/crates.io-index)",
@ -81,7 +81,7 @@ version = "2.32.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "atty 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
 "bitflags 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "strsim 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "textwrap 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
@ -115,6 +115,14 @@ dependencies = [
 "winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

+[[package]]
+name = "copy_dir"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "walkdir 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "dtoa"
 version = "0.4.3"
@ -287,7 +295,7 @@ dependencies = [

 [[package]]
 name = "proc-macro2"
-version = "0.4.8"
+version = "0.4.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
@ -300,10 +308,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"

 [[package]]
 name = "quote"
-version = "0.6.3"
+version = "0.6.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@ -377,9 +385,9 @@ name = "serde_derive"
 version = "1.0.70"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.14.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.14.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@ -394,7 +402,7 @@ dependencies = [

 [[package]]
 name = "slog"
-version = "2.2.3"
+version = "2.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"

 [[package]]
@ -402,7 +410,7 @@ name = "slog-async"
 version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "slog 2.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "slog 2.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "take_mut 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "thread_local 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -414,7 +422,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "chrono 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
 "isatty 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "slog 2.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "slog 2.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "term 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "thread_local 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -451,9 +459,9 @@ name = "structopt-derive"
 version = "0.2.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.14.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.14.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@ -468,11 +476,11 @@ dependencies = [

 [[package]]
 name = "syn"
-version = "0.14.4"
+version = "0.14.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
 "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@ -629,11 +637,21 @@ name = "void"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"

+[[package]]
+name = "walkdir"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "wasm-pack"
 version = "0.4.2"
 dependencies = [
 "console 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "copy_dir 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "human-panic 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "indicatif 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
@ -642,10 +660,11 @@ dependencies = [
 "serde 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde_derive 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde_json 1.0.24 (registry+https://github.com/rust-lang/crates.io-index)",
- "slog 2.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "slog 2.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "slog-async 2.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "slog-term 2.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "structopt 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tempdir 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
 "toml 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@ -689,7 +708,7 @@ dependencies = [
 [metadata]
 "checksum aho-corasick 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c1c6d463cbe7ed28720b5b489e7c083eeb8f90d08be2a0d6bb9e1ffea9ce1afa"
 "checksum ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
-"checksum atty 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)" = "2fc4a1aa4c24c0718a250f0681885c1af91419d242f29eb8f2ab28502d80dbd1"
+"checksum atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "9a7d5b8723950951411ee34d271d99dddcc2035a16ab25310ea2c8cfd4369652"
 "checksum backtrace 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)" = "89a47830402e9981c5c41223151efcced65a0510c13097c769cede7efb34782a"
 "checksum backtrace-sys 0.1.23 (registry+https://github.com/rust-lang/crates.io-index)" = "bff67d0c06556c0b8e6b5f090f0eac52d950d9dfd1d35ba04e4ca3543eaf6a7e"
 "checksum bitflags 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "d0c54bb8f454c567f21197eefcdbf5679d0bd99f2ddbe52e84c77061952e6789"
@ -700,6 +719,7 @@ dependencies = [
 "checksum clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b957d88f4b6a63b9d70d5f454ac8011819c6efa7727858f458ab71c756ce2d3e"
 "checksum clicolors-control 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1f84dec9bc083ce2503908cd305af98bd363da6f54bf8d4bf0ac14ee749ad5d1"
 "checksum console 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7649ca90478264b9686aac8d269fcb014f14c2bed7c79a7e51b9f6afd4d783eb"
+"checksum copy_dir 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6e4281031634644843bd2f5aa9c48cf98fc48d6b083bd90bb11becf10deaf8b0"
 "checksum dtoa 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6d301140eb411af13d3115f9a562c85cc6b541ade9dfa314132244aaee7489dd"
 "checksum failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "934799b6c1de475a012a02dab0ace1ace43789ee4b99bcfbf1a2e3e8ced5de82"
 "checksum failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c7cdda555bb90c9bb67a3b670a0f42de8e73f5981524123ad8578aafec8ddb8b"
@ -721,9 +741,9 @@ dependencies = [
 "checksum owning_ref 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "cdf84f41639e037b484f93433aa3897863b561ed65c6e59c7073d7c561710f37"
 "checksum parking_lot 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)" = "69376b761943787ebd5cc85a5bc95958651a22609c5c1c2b65de21786baec72b"
 "checksum parking_lot_core 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)" = "4db1a8ccf734a7bce794cc19b3df06ed87ab2f3907036b693c68f56b4d4537fa"
-"checksum proc-macro2 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)" = "c65b1ea15bb859d922cade2d1765b4b88beac339cbfad545ef2d2ef8c8215ee6"
+"checksum proc-macro2 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)" = "cccdc7557a98fe98453030f077df7f3a042052fae465bb61d2c2c41435cfd9b6"
 "checksum quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e920b65c65f10b2ae65c831a81a073a89edd28c7cce89475bff467ab4167a"
-"checksum quote 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)" = "e44651a0dc4cdd99f71c83b561e221f714912d11af1a4dff0631f923d53af035"
+"checksum quote 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)" = "b71f9f575d55555aa9c06188be9d4e2bfc83ed02537948ac0d520c24d0419f1a"
 "checksum rand 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "eba5f8cb59cc50ed56be8880a5c7b496bfd9bd26394e176bc67884094145c2c5"
 "checksum redox_syscall 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)" = "c214e91d3ecf43e9a4e41e578973adeb14b474f2bee858742d127af75a0112b1"
 "checksum redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7e891cfe48e9100a70a3b6eb652fef28920c117d366339687bd5576160db0f76"
@ -735,7 +755,7 @@ dependencies = [
 "checksum serde 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)" = "0c3adf19c07af6d186d91dae8927b83b0553d07ca56cbf7f2f32560455c91920"
 "checksum serde_derive 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)" = "3525a779832b08693031b8ecfb0de81cd71cfd3812088fafe9a7496789572124"
 "checksum serde_json 1.0.24 (registry+https://github.com/rust-lang/crates.io-index)" = "c3c6908c7b925cd6c590358a4034de93dbddb20c45e1d021931459fd419bf0e2"
-"checksum slog 2.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2f7bfce6405155042d42ec0e645efe43eddedd7be280063ce0623b120014e7f9"
+"checksum slog 2.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c43bcfcefccea70a0c52528be603b13237e76d7a031e6e1e92fabc344bd0a3aa"
 "checksum slog-async 2.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e544d16c6b230d84c866662fe55e31aacfca6ae71e6fc49ae9a311cb379bfc2f"
 "checksum slog-term 2.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5951a808c40f419922ee014c15b6ae1cd34d963538b57d8a4778b9ca3fff1e0b"
 "checksum smallvec 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)" = "26df3bb03ca5eac2e64192b723d51f56c1b1e0860e7c766281f4598f181acdc8"
@ -744,7 +764,7 @@ dependencies = [
 "checksum structopt 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)" = "d8e9ad6a11096cbecdcca0cc6aa403fdfdbaeda2fb3323a39c98e6a166a1e45a"
 "checksum structopt-derive 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)" = "4cbce8ccdc62166bd594c14396a3242bf94c337a51dbfa9be1076dd74b3db2af"
 "checksum syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)" = "d3b891b9015c88c576343b9b3e41c2c11a51c219ef067b264bd9c8aa9b441dad"
-"checksum syn 0.14.4 (registry+https://github.com/rust-lang/crates.io-index)" = "2beff8ebc3658f07512a413866875adddd20f4fd47b2a4e6c9da65cd281baaea"
+"checksum syn 0.14.5 (registry+https://github.com/rust-lang/crates.io-index)" = "4bad7abdf6633f07c7046b90484f1d9dc055eca39f8c991177b1046ce61dba9a"
 "checksum synom 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a393066ed9010ebaed60b9eafa373d4b1baac186dd7e008555b0f702b51945b6"
 "checksum synstructure 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3a761d12e6d8dcb4dcf952a7a89b475e3a9d69e4a69307e01a470977642914bd"
 "checksum take_mut 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f764005d11ee5f36500a149ace24e00e3da98b0158b3e2d53a7495660d3f4d60"
@ -766,6 +786,7 @@ dependencies = [
 "checksum uuid 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)" = "e1436e58182935dcd9ce0add9ea0b558e8a87befe01c1a301e6020aeb0876363"
 "checksum vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
 "checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
+"checksum walkdir 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "c66c0b9792f0a765345452775f3adbd28dde9d33f30d13e5dcc5ae17cf6f3780"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "773ef9dcc5f24b7d850d0ff101e542ff24c3b090a9768e03ff889fdef41f00fd"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
--- a/Cargo.toml
+++ b/Cargo.toml
@ -23,3 +23,7 @@ slog-term = "2.4"
 slog-async = "2.3"
 structopt = "0.2"
 toml = "0.4"
+
+[dev-dependencies]
+copy_dir = "0.1.2"
+tempdir = "0.3"
--- a/tests/all/main.rs
+++ b/tests/all/main.rs
@ -0,0 +1,11 @@
+extern crate copy_dir;
+extern crate failure;
+#[macro_use]
+extern crate serde_derive;
+extern crate serde_json;
+extern crate tempdir;
+extern crate wasm_pack;
+
+mod manifest;
+mod readme;
+mod utils;
--- a/tests/manifest/main.rs
+++ b/tests/manifest/main.rs
@ -1,16 +1,9 @@
-extern crate failure;
-#[macro_use]
-extern crate serde_derive;
-extern crate serde_json;
-extern crate wasm_pack;
-
-mod utils;
-
 use std::collections::HashSet;
 use std::fs;
 use std::path::PathBuf;

-use wasm_pack::manifest;
+use utils;
+use wasm_pack::{self, manifest};

 #[test]
 fn it_gets_the_crate_name_default_path() {
@ -60,14 +53,14 @@ fn it_recognizes_a_map_during_depcheck() {

 #[test]
 fn it_creates_a_package_json_default_path() {
+    let fixture = utils::fixture(".");
    let step = wasm_pack::progressbar::Step::new(1);
-    let path = PathBuf::from(".");
-    wasm_pack::command::init::create_pkg_dir(&path, &step).unwrap();
-    assert!(manifest::write_package_json(&path, &None, false, "", &step).is_ok());
-    let package_json_path = &path.join("pkg").join("package.json");
+    wasm_pack::command::init::create_pkg_dir(&fixture.path, &step).unwrap();
+    assert!(manifest::write_package_json(&fixture.path, &None, false, "", &step).is_ok());
+    let package_json_path = &fixture.path.join("pkg").join("package.json");
    assert!(fs::metadata(package_json_path).is_ok());
-    assert!(utils::read_package_json(&path).is_ok());
-    let pkg = utils::read_package_json(&path).unwrap();
+    assert!(utils::manifest::read_package_json(&fixture.path).is_ok());
+    let pkg = utils::manifest::read_package_json(&fixture.path).unwrap();
    assert_eq!(pkg.name, "wasm-pack");
    assert_eq!(pkg.repository.ty, "git");
    assert_eq!(
@ -88,14 +81,14 @@ fn it_creates_a_package_json_default_path() {

 #[test]
 fn it_creates_a_package_json_provided_path() {
+    let fixture = utils::fixture("tests/fixtures/js-hello-world");
    let step = wasm_pack::progressbar::Step::new(1);
-    let path = PathBuf::from("tests/fixtures/js-hello-world");
-    wasm_pack::command::init::create_pkg_dir(&path, &step).unwrap();
-    assert!(manifest::write_package_json(&path, &None, false, "", &step).is_ok());
-    let package_json_path = &path.join("pkg").join("package.json");
+    wasm_pack::command::init::create_pkg_dir(&fixture.path, &step).unwrap();
+    assert!(manifest::write_package_json(&fixture.path, &None, false, "", &step).is_ok());
+    let package_json_path = &fixture.path.join("pkg").join("package.json");
    assert!(fs::metadata(package_json_path).is_ok());
-    assert!(utils::read_package_json(&path).is_ok());
-    let pkg = utils::read_package_json(&path).unwrap();
+    assert!(utils::manifest::read_package_json(&fixture.path).is_ok());
+    let pkg = utils::manifest::read_package_json(&fixture.path).unwrap();
    assert_eq!(pkg.name, "js-hello-world");
    assert_eq!(pkg.main, "js_hello_world.js");

@ -109,16 +102,17 @@ fn it_creates_a_package_json_provided_path() {

 #[test]
 fn it_creates_a_package_json_provided_path_with_scope() {
+    let fixture = utils::fixture("tests/fixtures/scopes");
    let step = wasm_pack::progressbar::Step::new(1);
-    let path = PathBuf::from("tests/fixtures/scopes");
-    wasm_pack::command::init::create_pkg_dir(&path, &step).unwrap();
+    wasm_pack::command::init::create_pkg_dir(&fixture.path, &step).unwrap();
    assert!(
-        manifest::write_package_json(&path, &Some("test".to_string()), false, "", &step).is_ok()
+        manifest::write_package_json(&fixture.path, &Some("test".to_string()), false, "", &step)
+            .is_ok()
    );
-    let package_json_path = &path.join("pkg").join("package.json");
+    let package_json_path = &fixture.path.join("pkg").join("package.json");
    assert!(fs::metadata(package_json_path).is_ok());
-    assert!(utils::read_package_json(&path).is_ok());
-    let pkg = utils::read_package_json(&path).unwrap();
+    assert!(utils::manifest::read_package_json(&fixture.path).is_ok());
+    let pkg = utils::manifest::read_package_json(&fixture.path).unwrap();
    assert_eq!(pkg.name, "@test/scopes-hello-world");
    assert_eq!(pkg.main, "scopes_hello_world.js");

@ -132,14 +126,14 @@ fn it_creates_a_package_json_provided_path_with_scope() {

 #[test]
 fn it_creates_a_pkg_json_with_correct_files_on_node() {
+    let fixture = utils::fixture(".");
    let step = wasm_pack::progressbar::Step::new(1);
-    let path = PathBuf::from(".");
-    wasm_pack::command::init::create_pkg_dir(&path, &step).unwrap();
-    assert!(manifest::write_package_json(&path, &None, false, "nodejs", &step).is_ok());
-    let package_json_path = &path.join("pkg").join("package.json");
+    wasm_pack::command::init::create_pkg_dir(&fixture.path, &step).unwrap();
+    assert!(manifest::write_package_json(&fixture.path, &None, false, "nodejs", &step).is_ok());
+    let package_json_path = &fixture.path.join("pkg").join("package.json");
    assert!(fs::metadata(package_json_path).is_ok());
-    assert!(utils::read_package_json(&path).is_ok());
-    let pkg = utils::read_package_json(&path).unwrap();
+    assert!(utils::manifest::read_package_json(&fixture.path).is_ok());
+    let pkg = utils::manifest::read_package_json(&fixture.path).unwrap();
    assert_eq!(pkg.name, "wasm-pack");
    assert_eq!(pkg.repository.ty, "git");
    assert_eq!(
@ -161,14 +155,14 @@ fn it_creates_a_pkg_json_with_correct_files_on_node() {

 #[test]
 fn it_creates_a_package_json_with_correct_keys_when_types_are_skipped() {
+    let fixture = utils::fixture(".");
    let step = wasm_pack::progressbar::Step::new(1);
-    let path = PathBuf::from(".");
-    wasm_pack::command::init::create_pkg_dir(&path, &step).unwrap();
-    assert!(manifest::write_package_json(&path, &None, true, "", &step).is_ok());
-    let package_json_path = &path.join("pkg").join("package.json");
+    wasm_pack::command::init::create_pkg_dir(&fixture.path, &step).unwrap();
+    assert!(manifest::write_package_json(&fixture.path, &None, true, "", &step).is_ok());
+    let package_json_path = &fixture.path.join("pkg").join("package.json");
    assert!(fs::metadata(package_json_path).is_ok());
-    assert!(utils::read_package_json(&path).is_ok());
-    let pkg = utils::read_package_json(&path).unwrap();
+    assert!(utils::manifest::read_package_json(&fixture.path).is_ok());
+    let pkg = utils::manifest::read_package_json(&fixture.path).unwrap();
    assert_eq!(pkg.name, "wasm-pack");
    assert_eq!(pkg.repository.ty, "git");
    assert_eq!(
@ -187,16 +181,14 @@ fn it_creates_a_package_json_with_correct_keys_when_types_are_skipped() {

 #[test]
 fn it_errors_when_wasm_bindgen_is_not_declared() {
+    let fixture = utils::fixture("tests/fixtures/bad-cargo-toml");
    let step = wasm_pack::progressbar::Step::new(1);
-    assert!(
-        manifest::check_crate_config(&PathBuf::from("tests/fixtures/bad-cargo-toml"), &step)
-            .is_err()
-    );
+    assert!(manifest::check_crate_config(&fixture.path, &step).is_err());
 }

 #[test]
 fn it_does_not_error_when_wasm_bindgen_is_declared() {
+    let fixture = utils::fixture("tests/fixtures/js-hello-world");
    let step = wasm_pack::progressbar::Step::new(1);
-    let path = PathBuf::from("tests/fixtures/js-hello-world");
-    assert!(manifest::check_crate_config(&path, &step).is_ok());
+    assert!(manifest::check_crate_config(&fixture.path, &step).is_ok());
 }
--- a/tests/all/readme.rs
+++ b/tests/all/readme.rs
@ -0,0 +1,37 @@
+extern crate failure;
+extern crate wasm_pack;
+
+use std::fs;
+
+use utils;
+use wasm_pack::readme;
+
+#[test]
+fn it_copies_a_readme_default_path() {
+    let fixture = utils::fixture(".");
+    fs::create_dir(fixture.path.join("pkg")).expect("should create pkg directory OK");
+
+    let step = wasm_pack::progressbar::Step::new(1);
+    assert!(readme::copy_from_crate(&fixture.path, &step).is_ok());
+    let crate_readme_path = fixture.path.join("README.md");
+    let pkg_readme_path = fixture.path.join("pkg").join("README.md");
+    assert!(fs::metadata(&pkg_readme_path).is_ok());
+    let crate_readme = utils::readme::read_file(&crate_readme_path).unwrap();
+    let pkg_readme = utils::readme::read_file(&pkg_readme_path).unwrap();
+    assert_eq!(crate_readme, pkg_readme);
+}
+
+#[test]
+fn it_creates_a_package_json_provided_path() {
+    let fixture = utils::fixture("tests/fixtures/js-hello-world");
+    fs::create_dir(fixture.path.join("pkg")).expect("should create pkg directory OK");
+
+    let step = wasm_pack::progressbar::Step::new(1);
+    assert!(readme::copy_from_crate(&fixture.path, &step).is_ok());
+    let crate_readme_path = fixture.path.join("README.md");
+    let pkg_readme_path = fixture.path.join("pkg").join("README.md");
+    assert!(fs::metadata(&pkg_readme_path).is_ok());
+    let crate_readme = utils::readme::read_file(&crate_readme_path).unwrap();
+    let pkg_readme = utils::readme::read_file(&pkg_readme_path).unwrap();
+    assert_eq!(crate_readme, pkg_readme);
+}
--- a/tests/all/utils.rs
+++ b/tests/all/utils.rs
@ -0,0 +1,77 @@
+use std::path::{Path, PathBuf};
+
+use copy_dir::copy_dir;
+use tempdir;
+
+/// Copy the given fixture into a unique temporary directory. This allows the
+/// test to mutate the copied fixture without messing up other tests that are
+/// also trying to read from or write to that fixture. The given path should be
+/// relative from the root of the repository, eg
+/// "tests/fixtures/im-from-brooklyn-the-place-where-stars-are-born".
+pub fn fixture<P>(fixture: P) -> Fixture
+where
+    P: AsRef<Path>,
+{
+    let dir = tempdir::TempDir::new("wasm-pack").expect("should create temporary directory OK");
+    let path = dir.path().join("fixture");
+    copy_dir(fixture, &path).expect("should copy fixture directory into temporary directory OK");
+    Fixture { dir, path }
+}
+
+pub struct Fixture {
+    pub dir: tempdir::TempDir,
+    pub path: PathBuf,
+}
+
+pub mod manifest {
+    use std::fs::File;
+    use std::io::prelude::*;
+    use std::path::Path;
+
+    use failure::Error;
+    use serde_json;
+
+    #[derive(Deserialize)]
+    pub struct NpmPackage {
+        pub name: String,
+        pub description: String,
+        pub version: String,
+        pub license: String,
+        pub repository: Repository,
+        pub files: Vec<String>,
+        pub main: String,
+        pub types: Option<String>,
+    }
+
+    #[derive(Deserialize)]
+    pub struct Repository {
+        #[serde(rename = "type")]
+        pub ty: String,
+        pub url: String,
+    }
+
+    pub fn read_package_json(path: &Path) -> Result<NpmPackage, Error> {
+        let manifest_path = path.join("pkg").join("package.json");
+        let mut pkg_file = File::open(manifest_path)?;
+        let mut pkg_contents = String::new();
+        pkg_file.read_to_string(&mut pkg_contents)?;
+
+        Ok(serde_json::from_str(&pkg_contents)?)
+    }
+}
+
+pub mod readme {
+    use std::fs::File;
+    use std::io::Read;
+    use std::path::Path;
+
+    use failure::Error;
+
+    pub fn read_file(path: &Path) -> Result<String, Error> {
+        let mut file = File::open(path)?;
+        let mut contents = String::new();
+        file.read_to_string(&mut contents)?;
+
+        Ok(contents)
+    }
+}
--- a/tests/manifest/utils.rs
+++ b/tests/manifest/utils.rs
@ -1,34 +0,0 @@
-use std::fs::File;
-use std::io::prelude::*;
-use std::path::Path;
-
-use failure::Error;
-use serde_json;
-
-#[derive(Deserialize)]
-pub struct NpmPackage {
-    pub name: String,
-    pub description: String,
-    pub version: String,
-    pub license: String,
-    pub repository: Repository,
-    pub files: Vec<String>,
-    pub main: String,
-    pub types: Option<String>,
-}
-
-#[derive(Deserialize)]
-pub struct Repository {
-    #[serde(rename = "type")]
-    pub ty: String,
-    pub url: String,
-}
-
-pub fn read_package_json(path: &Path) -> Result<NpmPackage, Error> {
-    let manifest_path = path.join("pkg").join("package.json");
-    let mut pkg_file = File::open(manifest_path)?;
-    let mut pkg_contents = String::new();
-    pkg_file.read_to_string(&mut pkg_contents)?;
-
-    Ok(serde_json::from_str(&pkg_contents)?)
-}
--- a/tests/readme/main.rs
+++ b/tests/readme/main.rs
@ -1,35 +0,0 @@
-extern crate failure;
-extern crate wasm_pack;
-
-mod utils;
-
-use std::fs;
-use std::path::PathBuf;
-
-use wasm_pack::readme;
-
-#[test]
-fn it_copies_a_readme_default_path() {
-    let step = wasm_pack::progressbar::Step::new(1);
-    let path = PathBuf::from(".");
-    assert!(readme::copy_from_crate(&path, &step).is_ok());
-    let crate_readme_path = &path.join("README.md");
-    let pkg_readme_path = &path.join("pkg").join("README.md");
-    assert!(fs::metadata(&pkg_readme_path).is_ok());
-    let crate_readme = utils::read_file(&crate_readme_path).unwrap();
-    let pkg_readme = utils::read_file(&pkg_readme_path).unwrap();
-    assert_eq!(crate_readme, pkg_readme);
-}
-
-#[test]
-fn it_creates_a_package_json_provided_path() {
-    let step = wasm_pack::progressbar::Step::new(1);
-    let path = PathBuf::from("tests/fixtures/js-hello-world");
-    assert!(readme::copy_from_crate(&path, &step).is_ok());
-    let crate_readme_path = &path.join("README.md");
-    let pkg_readme_path = &path.join("pkg").join("README.md");
-    assert!(fs::metadata(&pkg_readme_path).is_ok());
-    let crate_readme = utils::read_file(&crate_readme_path).unwrap();
-    let pkg_readme = utils::read_file(&pkg_readme_path).unwrap();
-    assert_eq!(crate_readme, pkg_readme);
-}
--- a/tests/readme/utils.rs
+++ b/tests/readme/utils.rs
@ -1,12 +0,0 @@
-use failure::Error;
-use std::fs::File;
-use std::io::Read;
-use std::path::Path;
-
-pub fn read_file(path: &Path) -> Result<String, Error> {
-    let mut file = File::open(path)?;
-    let mut contents = String::new();
-    file.read_to_string(&mut contents)?;
-
-    Ok(contents)
-}