ci: Add coverage report to the GitHub Actions summary (#20)

Co-authored-by: Mark Walker <theshow@gmail.com>

.github/workflows/main.yml

@@ -10,6 +10,14 @@ concurrency:
   group: ${{ github.head_ref || github.run_id }}
   cancel-in-progress: true
 
+env:
+  FORCE_COLOR: "1" # Make tools pretty.
+  TOX_TESTENV_PASSENV: FORCE_COLOR
+  PIP_DISABLE_PIP_VERSION_CHECK: "1"
+  PIP_NO_PYTHON_VERSION_WARNING: "1"
+  # Keep in sync with .pre-commit-config.yaml/default_language_version/python.
+  PYTHON_LATEST: "3.12"
+
 jobs:
   tests:
     name: Python ${{ matrix.python-version }}
@@ -33,8 +41,8 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install --upgrade pip setuptools wheel
-          python -m pip install --upgrade 'tox>=4.0.0rc3'
+          python -Im pip install --upgrade pip setuptools wheel
+          python -Im pip install --upgrade 'tox>=4.7'
 
       - name: Run tox targets for ${{ matrix.python-version }}
         run: tox run -f py$(echo ${{ matrix.python-version }} | tr -d .)
@@ -54,10 +62,10 @@ jobs:
 
       - uses: actions/setup-python@v5
         with:
-          python-version: '3.12'
+          python-version: ${{env.PYTHON_LATEST}}
 
       - name: Install dependencies
-        run: python -m pip install --upgrade coverage[toml]
+        run: python -Im pip install --upgrade coverage[toml]
 
       - name: Download data
         uses: actions/download-artifact@v4
@@ -68,9 +76,11 @@ jobs:
 
       - name: Combine coverage and fail if it's <100%
         run: |
-          python -m coverage combine
-          python -m coverage html --skip-covered --skip-empty
-          python -m coverage report
+          python -Im coverage combine
+          python -Im coverage html --skip-covered --skip-empty
+          python -Im coverage report
+          echo "## Coverage summary" >> $GITHUB_STEP_SUMMARY
+          python -Im coverage report --format=markdown >> $GITHUB_STEP_SUMMARY
 
       - name: Upload HTML report
         if: ${{ failure() }}

tox.ini

@@ -16,3 +16,7 @@ deps = -r requirements/{envname}.txt
 package = wheel
 set_env =
     PYTHONDEVMODE = 1
+
+pass_env =
+    FORCE_COLOR
+    NO_COLOR