Generate coverage reports using only GitHub Actions, without codecov.io

.github/workflows/ci.yml

@@ -96,8 +96,20 @@ jobs:
 
     - run: nox --python ${{ matrix.python.action }} -e ${{ matrix.task.nox }} -- --use-wheel dist/*.whl
 
+    - name: Store coverage file
+      uses: actions/upload-artifact@v3
+      with:
+        # We have a single artifact shared for each workflow run.
+        # in this way we should intefere with coverage reports from other PRs
+        # or previous runs for the same PR.
+        name: coverage-${{ github.run_id }}
+        # Is important to keep the unique names for the coverage files
+        # so that when uploaded to the same artifact, they don't overlap.
+        path: .coverage.*
+
     - name: Codecov
       run: |
+        coverage combine
         codecov -n "GitHub Actions - ${{ matrix.task.name}} - ${{ matrix.os.name }} ${{ matrix.python.name }}"
 
 
@@ -232,6 +244,37 @@ jobs:
         password: ${{ secrets.PYPI_TOKEN }}
         verbose: true
 
+  coverage-report:
+    name: Coverage report
+    runs-on: ubuntu-latest
+    needs:
+      # We are waiting only for test jobs.
+      - test-linux
+      - test-windows
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Install dependencies
+      run: python -m pip install --upgrade pip coverage[toml] diff_cover
+
+    - name: Download coverage reports
+      uses: actions/download-artifact@v3
+      with:
+        name: coverage-${{ github.run_id }}
+        path: .
+
+    - name: Combine coverage
+      run: coverage combine
+
+    - name: Report coverage
+      run: coverage report
+
+    - name: Diff coverage
+      run: |
+        coverage xml
+        diff-cover --fail-under=100 coverage.xml
+
+
   # This is a meta-job to simplify PR CI enforcement configuration in GitHub.
   # Inside the GitHub config UI you only configure this job as required.
   # All the extra requirements are defined "as code" as part of the `needs`

.gitignore

@@ -11,6 +11,7 @@ dist/
 venv/
 htmlcov/
 .coverage
+coverage.xml
 *~
 *.lock
 apidocs/

noxfile.py

@@ -36,9 +36,8 @@ def tests(session: nox.Session) -> None:
     session.run("coverage", "run", "--module", "twisted.trial", *posargs)
 
     if os.environ.get("CI") != "true":
+        # When running the test localy, show the coverage report.
         session.notify("coverage_report")
-    else:
-        session.run("coverage", "combine")
 
 
 @nox.session