GHA: Run tests on multiple platforms (#275)

* GHA: run tests on ubuntu-, windows- and macos- latest

* GHA: merge clippy CI pipelines

* only run windows tests using virtual memory single threaded

* GHA: clean-up a bit

* GHA: rename RUSTC_FLAGS to TEST_FLAGS

* GHA: rename rustc-args to test-args

.github/workflows/rust.yml

@@ -39,7 +39,16 @@ jobs:
 
   test:
     name: Test
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+        include:
+          # Include a new variable `rustc-args` with `-- --test-threads 1`
+          # for windows-latest to be used with virtual_memory crate feature
+          # enabled while testing.
+          - os: windows-latest
+            test-args: "--test-threads 1"
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
@@ -58,9 +67,10 @@ jobs:
       - uses: actions-rs/cargo@v1
         env:
           RUSTFLAGS: '--cfg debug_assertions'
+          TEST_FLAGS: ${{ matrix.test-args }}
         with:
           command: test
-          args: --release --features virtual_memory
+          args: --release --features virtual_memory -- $TEST_FLAGS
 
   fmt:
     name: Formatting
@@ -97,18 +107,6 @@ jobs:
         with:
           command: clippy
           args: --features virtual_memory -- -D warnings
-
-  clippy_no_std:
-    name: Clippy (no_std)
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-      - uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: nightly
-          override: true
-          components: clippy
       - uses: actions-rs/cargo@v1
         with:
           command: clippy