Add code coverage calculation

Add code coverage
Add upload to codecov
Add badge to readme

Author: dancergraham

.github/workflows/python-package.yml

@@ -125,13 +125,41 @@ jobs:
         run: |
           sphinx-build -b html docs docs/_build
 
+  coverage:
+    runs-on: ubuntu-latest
+    needs: test
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python 3.13
+        uses: actions/setup-python@v5
+        with:
+          python-version: 3.13
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install coverage codecov
+          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+      - name: Run coverage
+        run: |
+          coverage run --source=waffle -m pytest
+          coverage report
+          coverage xml
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v5
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          files: ./coverage.xml
+          flags: unittests
+          name: codecov-umbrella
+
   release-production:
     # Only upload if a tag is pushed (otherwise just build & check)
     if: github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags')
 
     runs-on: ubuntu-latest
 
-    needs: [test, lint, i18n, docs]
+    needs: [test, lint, i18n, docs, coverage]
 
     steps:
       - uses: actions/checkout@v4

README.rst

@@ -18,7 +18,9 @@ a number of ways.
 .. image:: https://img.shields.io/readthedocs/waffle
    :target: https://app.readthedocs.org/projects/waffle
    :alt: Read the Docs
-
+.. image:: https://codecov.io/gh/jazzband/django-waffle/branch/master/graph/badge.svg
+   :target: https://codecov.io/gh/jazzband/django-waffle
+   :alt: Codecov
 
 :Code:          https://github.com/jazzband/django-waffle
 :License:       BSD; see LICENSE file

requirements/test.txt

@@ -1,2 +1,3 @@
 ruff
 tox
+coverage

tox.ini

@@ -5,6 +5,7 @@ envlist =
     py{311}-django{42,50,51}
     py{312}-django{42,50,51}
     py{313}-django{51}
+    coverage
 isolated_build = True
 
 [gh-actions]
@@ -42,3 +43,13 @@ deps =
 	-r{toxinidir}/requirements.txt
 commands =
     ./run.sh typecheck
+
+[testenv:coverage]
+deps =
+    coverage
+    Django>=4.2,<5.2
+    -r{toxinidir}/requirements.txt
+commands =
+    coverage run --source=waffle ./run.sh test
+    coverage report
+    coverage html