Update configuration to include test coverage

This includes adding necessary pip requirements, adding a `.coveragerc`
file, updating the pytest configuration, and updating the `test` job in
the `build` workflow for GitHub Actions.

.coveragerc

@@ -0,0 +1,12 @@
+# This is the configuration for code coverage checks
+# https://coverage.readthedocs.io/en/latest/config.html
+
+[run]
+source = cisagov_lambda
+omit =
+branch = true
+
+[report]
+exclude_lines =
+    if __name__ == "__main__":
+show_missing = true

.github/workflows/build.yml

@@ -216,6 +216,12 @@ jobs:
         # is not installed into the local `pip` environment Please see:
         # https://docs.pytest.org/en/7.1.x/explanation/pythonpath.html#invoking-pytest-versus-python-m-pytest
         run: python -m pytest
+      - name: Upload coverage report
+        run: coveralls
+        env:
+          COVERALLS_SERVICE_NAME: github
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        if: success()
       - name: Setup tmate debug session
         uses: mxschmitt/action-tmate@v3
         if: env.RUN_TMATE

.gitignore

@@ -7,5 +7,7 @@ lambda_build.zip
 
 ## Python ##
 __pycache__
+.coverage
 .mypy_cache
+.pytest_cache
 .python-version

pytest.ini

@@ -1,3 +1,4 @@
 [pytest]
-# Increase verbosity and display extra test summary info for tests that did not pass
-addopts = --verbose -ra
+# Increase verbosity, display extra test summary info for tests that did not
+# pass, and report test coverage information.
+addopts = --verbose -ra --cov

requirements-test.txt

@@ -1,4 +1,15 @@
 --requirement requirements.txt
+coverage
+# coveralls 1.11.0 added a service number for calls from
+# GitHub Actions. This caused a regression which resulted in a 422
+# response from the coveralls API with the message:
+# Unprocessable Entity for url: https://coveralls.io/api/v1/jobs
+# 1.11.1 fixed this issue, but to ensure expected behavior we'll pin
+# to never grab the regression version.
+coveralls != 1.11.0
+# This is required to install project dependencies so that pytest can be run
+# successfully.
 pipenv
 pre-commit
 pytest
+pytest-cov