Add thread sanitizer to test (#72)

.github/workflows/test.yaml

@@ -213,3 +213,36 @@ jobs:
           PROPTEST_CASES: "10"
           MIRIFLAGS: "-Zmiri-disable-isolation"
         run: cargo miri test --all-features
+
+  thread_sanitizer-MacOS:
+    name: Thread Sanitizer checks MacOS
+    runs-on: macos-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/cache@v2
+      with:
+        path: |
+          ~/.cargo/bin/
+          ~/.cargo/registry/index/
+          ~/.cargo/registry/cache/
+          ~/.cargo/git/db/
+          target/
+        key: ${{ github.event.repository.name }}-${{ runner.os }}-cargo-thread_sanitizer-v2
+    - name: Install latest nightly
+      uses: actions-rs/toolchain@v1
+      with:
+          toolchain: nightly
+          override: true
+          components: rust-src
+    - name: Run thread sanitizer
+      run: |
+        # Thread sanitizer isn't guaranteed to catch all data races, it can only catch it
+        # the data race if it happens when running the program.
+        #
+        # Running the tests multiple times increase the chances that data races are found
+        # by the thread sanitizer.
+        for _ in $(seq 1 10); do cargo +nightly test -Z build-std --target --target $(uname -m)-apple-darwin; done
+      env:
+        RUSTDOCFLAGS: "-Zsanitizer=thread"
+        RUSTFLAGS: "-Zsanitizer=thread"