ci: reduce the number of CI jobs (#28)

With 3 operating systems, 3 rust versions, and 2 set of arguments for cargo-test, the combinations in the test matrix grew to 18 (3x3x2) jobs. This reduces the number of jobs while introduces tests in more platforms.

.github/workflows/tests.yaml

@@ -1,45 +1,80 @@
-name: Test suite
-
-on: [push, pull_request]
-
+name: Tests
+on:
+  pull_request:
+  push:
 jobs:
-  tests:
-    name: Run tests
+  test:
+    name: test
+    env:
+      CARGO_TERM_COLOR: always
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ ubuntu-latest, windows-latest, macOS-latest ]
-        rust:
-        - stable
-        - nightly
-        - 1.66.1  # Minimum Supported Rust Version (MSRV)
-        cargo-test-args:
-        - "--features=test_proto2-module,test_proto3-module,ascii-tree"
-        - "--features=constant-folding,test_proto2-module,test_proto3-module,ascii-tree"
-    env:
-      CARGO_TERM_COLOR: always
+        build:
+          - msrv
+          - stable
+          - nightly
+          - macos
+          - win-msvc
+          - win-gnu
+          - constant-folding-off
+        include:
+          - build: msrv
+            os: ubuntu-latest
+            rust: 1.66.1
+            args: ""
+
+          - build: stable
+            os: ubuntu-latest
+            rust: stable
+            args: ""
+
+          - build: nightly
+            os: ubuntu-latest
+            rust: nightly
+            args: ""
+
+          - build: macos
+            os: macos-latest
+            rust: stable
+            args: ""
+
+          - build: win-msvc
+            os: windows-latest
+            rust: stable
+            args: ""
+
+          - build: win-gnu
+            os: windows-latest
+            rust: stable-x86_64-gnu
+            args: ""
+
+          - build: constant-folding-off
+            os: ubuntu-latest
+            rust: stable
+            args: "--no-default-features --features=test_proto2-module,test_proto3-module,ascii-tree"
     steps:
-    - name: Checkout sources
-      uses: actions/checkout@v3
+      - name: Checkout sources
+        uses: actions/checkout@v3
 
-    - name: Setup cache
-      uses: actions/cache@v3
-      with:
-        path: |
+      - name: Setup cache
+        uses: actions/cache@v3
+        with:
+          path: |
             ~/.cargo/registry
             ~/.cargo/git
             target
-        key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
-
-    - name: Install Rust toolchain
-      uses: dtolnay/rust-toolchain@master
-      with:
-        toolchain: ${{ matrix.rust }}
-
-    - name: Run cargo test
-      uses: actions-rs/cargo@v1
-      with:
-        command: test
-        args: --workspace --all-targets --no-default-features ${{ matrix.cargo-test-args }}
-      env:
-        RUSTFLAGS: -Awarnings  # Allow all warnings
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ matrix.rust }}
+
+      - name: Run cargo test
+        uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --workspace --all-targets ${{ matrix.args }}
+        env:
+          RUSTFLAGS: -Awarnings # Allow all warnings