Also run cargo test on macOS and Windows

Author: messense

.github/workflows/main.yml

@@ -4,15 +4,18 @@ on: [push, pull_request]
 jobs:
   test:
     name: Test
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
     strategy:
       matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
         rust: [stable, beta, nightly]
     steps:
     - uses: actions/checkout@master
     - name: Install Rust
       run: rustup update ${{ matrix.rust }} && rustup default ${{ matrix.rust }}
     - run: cargo test
+    - name: Integration test
+      run: cargo test --manifest-path test-crate/Cargo.toml
 
   rustfmt:
     name: Rustfmt