MAINT: Add codecov support

.github/workflows/pytest.yaml

@@ -31,4 +31,27 @@ jobs:
     - run: python -m pip install dist/*.whl
     - run: python -m pip install pytest
     - run: python -m pip list
-    - run: python -m pytest -v --pyargs kawin
+    # pytest:
+    # - The `--import-mode=append` and `--pyargs pycalphad` flags test the installed package over the local one
+    # - The `--cov` flag is required to turn on coverage
+    - run: pytest -v --import-mode=append --cov --cov-config=pyproject.toml --pyargs kawin
+    - run: coverage xml
+    - uses: actions/upload-artifact@v4
+      with:
+        name: coverage-${{ matrix.os }}-${{ matrix.python-version }}
+        path: coverage.xml
+
+  Upload-Coverage:
+    runs-on: ubuntu-latest
+    needs: [Tests]
+    steps:
+      # The source code _must_ be checked out for coverage to be processed at Codecov.
+      - uses: actions/checkout@v4
+      - name: Download artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: coverage-*
+      - name: Upload to Codecov
+        uses: codecov/codecov-action@v3
+        with:
+          fail_ci_if_error: true

pyproject.toml

@@ -5,3 +5,18 @@ requires = [
 ]
 
 build-backend = "setuptools.build_meta"
+
+[tool.coverage.paths]
+# The first path is the path to the modules to report coverage against.
+# All following paths are patterns to match against the collected data.
+# Any matches will be combined with the first path for coverage.
+source = [
+    "./kawin",
+    "*/lib/*/site-packages/kawin",  # allows testing against site-packages for a local virtual environment
+]
+
+[tool.coverage.run]
+# Only consider coverage for these packages:
+source_pkgs = [
+    "kawin"
+]