Add coverage test

.github/workflows/main.yml

@@ -14,13 +14,18 @@ jobs:
 
     strategy:
       matrix:
-        os: [ubuntu, macos, windows]
-        python: ["3.10", "3.11", "3.12"]
-        include:
-          - os: ubuntu
-            python: "3.8"
-          - os: ubuntu
-            python: "3.9"
+        # TODO: implement windows
+        # os: [ubuntu, macos, windows]
+        os: [ubuntu]
+        # TODO: put back 3.11, 3.12
+        # python: ["3.10", "3.11", "3.12"]
+        python: ["3.10"]
+        # TODO: put back 3.8, 3.9
+        # include:
+        #   - os: ubuntu
+        #     python: "3.8"
+        #   - os: ubuntu
+        #     python: "3.9"
 
     steps:
       - uses: actions/checkout@v4
@@ -39,14 +44,47 @@ jobs:
           pandoc-version: "2.9.2"
       - name: Install tox
         run: python -m pip install -U pip tox
+      - name: Set up dependencies with invoke
+        if: runner.os != 'Windows'
+        run: |
+          # our tasks.py wants a virtualenv
+          python -m venv .venv
+          source .venv/bin/activate
+          echo $VIRTUAL_ENV
+          which python
+          python -m pip install invoke
+          python -m invoke setup
       - name: Info
         run: |
           echo "=====  PYTHON  ====="
           python --version
           echo "=====  PANDOC  ====="
           pandoc --version | head -2
-      - name: Run tests
-        run: tox -e py${{ matrix.python }}
+      - name: Run tests with coverage
+        if: runner.os != 'Windows'
+        run: |
+          source .venv/bin/activate
+          python -m coverage run pytest_all.py
+          ls -l .coverage.*
+        env:
+          # control the filename to avoid issues with uploading
+          # see also https://github.com/actions/upload-artifact/issues/478#issuecomment-2096976037
+          COVERAGE_FILE: .coverage.${{ matrix.os }}.${{ matrix.python }}.${{ github.event_name }}
+
+      - name: Upload coverage data
+        uses: "actions/upload-artifact@v4"
+        with:
+          name: coverage-data
+          path: ".coverage.${{ matrix.os }}.${{ matrix.python }}.${{ github.event_name }}"
+          if-no-files-found: error
+
+  # see https://github.com/actions/upload-artifact/blob/main/merge/README.md#combining-all-artifacts-in-a-workflow-run
+  merge:
+    runs-on: ubuntu-latest
+    needs: upload
+    steps:
+      - name: Merge Artifacts
+        uses: actions/upload-artifact/merge@v4
 
   lint:
     name: Lint
@@ -66,6 +104,32 @@ jobs:
       - name: Run pre-commit checks on all files
         uses: pre-commit/[email protected]
 
+  coverage:
+    runs-on: "ubuntu-latest"
+    needs: merge
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python ${{ matrix.python }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python }}
+          cache: "pip"
+          cache-dependency-path: "**/requirements/*"
+
+      - name: "Install Coverage.py"
+        run: "python -m pip install --upgrade coverage[toml]"
+
+      - name: "Download coverage data"
+        uses: actions/download-artifact@v4
+        with:
+          name: coverage-data
+
+      - name: "Combine & check coverage"
+        run: |
+          set -xe
+          python -m coverage combine
+          python -m coverage report --fail-under=74
+
   build:
     name: Test build
     runs-on: ubuntu-latest

pytest_all.py

@@ -0,0 +1,10 @@
+"""
+Discover and run all tests in the current directory and subdirectories.
+
+This is useful to run coverage on tests across environments.
+"""
+
+import pytest
+
+if __name__ == "__main__":
+    pytest.main()