ci(tests): add choice of OS + coverage

Author: amyheather

.github/workflows/tests.yaml

@@ -1,42 +1,47 @@
-# This file runs the tests in `tests/`
-# They will run in parallel, and run on three operating systems:
-# Ubuntu, Windows and Mac.
-
 name: tests
 
 on:
   push:
     branches: [main]
   workflow_dispatch:
+    inputs:
+      operating_systems:
+        description: 'Operating systems to test on'
+        type: choice
+        default: 'all'
+        options:
+          - all
+          - ubuntu-latest
+          - windows-latest
+          - macos-latest
 
 jobs:
-
-  # Run tests on Ubuntu
-  tests-on-ubuntu:
+  # Generate matrix based on input
+  setup-matrix:
     runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
     steps:
-
-      - name: Check out repository
-        uses: actions/checkout@v4
-
-      - name: Install python and dependencies
-        uses: actions/setup-python@v4
-        with:
-          python-version: '3.13'
-          cache: 'pip'
-      - run: pip install -r requirements.txt
-
-      - name: Run tests
-        run: pytest
-
-      - name: List the environment variables
-        run: env
-
-  # Run tests on Windows
-  tests-on-windows:
-    runs-on: windows-latest
+      - name: Set matrix
+        id: set-matrix
+        run: |
+          if [[ "${{ inputs.operating_systems }}" == "all" || "${{ github.event_name }}" == "push" ]]; then
+            echo 'matrix=["ubuntu-latest", "windows-latest", "macos-latest"]' >> $GITHUB_OUTPUT
+          else
+            echo 'matrix=["${{ inputs.operating_systems }}"]' >> $GITHUB_OUTPUT
+          fi
+
+  # Run tests using matrix strategy
+  tests:
+    permissions:
+      contents: write
+    needs: setup-matrix
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: ${{ fromJSON(needs.setup-matrix.outputs.matrix) }}
+    
     steps:
-
       - name: Check out repository
         uses: actions/checkout@v4
 
@@ -45,31 +50,42 @@ jobs:
         with:
           python-version: '3.13'
           cache: 'pip'
-      - run: python -m pip install -r requirements.txt
-
-      - name: Run tests
-        run: pytest
-
-      - name: List the environment variables
-        run: env
-
-  # Run tests on Mac
-  tests-on-macos:
-    runs-on: macos-latest
-    steps:
-
-      - name: Check out repository
-        uses: actions/checkout@v4
-
-      - name: Install python and dependencies
-        uses: actions/setup-python@v4
+      
+      - name: Install requirements (Windows)
+        if: runner.os == 'Windows'
+        run: python -m pip install -r requirements.txt
+      
+      - name: Install requirements (Unix)
+        if: runner.os != 'Windows'
+        run: pip install -r requirements.txt
+
+      - name: Run tests (with coverage for linux)
+        run: |
+          if [ "${{ matrix.os }}" = "ubuntu-latest" ]; then
+            pytest --cov --cov-report=xml
+          else
+            pytest
+          fi
+        shell: bash
+
+      - name: Generate coverage badge (for-the-badge style)
+        if: matrix.os == 'ubuntu-latest'
+        run: genbadge coverage -i coverage.xml -o images/coverage-badge.svg
+
+      - name: Upload coverage badge
+        if: matrix.os == 'ubuntu-latest'
+        uses: actions/upload-artifact@v4
         with:
-          python-version: '3.13'
-          cache: 'pip'
-      - run: pip install -r requirements.txt
-
-      - name: Run tests
-        run: pytest
-
-      - name: List the environment variables
-        run: env
+          name: coverage-badge
+          path: images/coverage-badge.svg
+
+      - name: Commit coverage badge
+        if: matrix.os == 'ubuntu-latest'
+        run: |
+          git config --local user.email "github-actions[bot]@users.noreply.github.com"
+          git config --local user.name "github-actions[bot]"
+          git add images/coverage-badge.svg
+          git commit -m "ci(tests): update coverage badge" || echo "No changes to commit"
+          git push
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}