test: Fix coverage reporting

By adding the current working directory to the `sys.path`.

Author: davidparsson

.github/workflows/ci.yml

@@ -34,7 +34,11 @@ jobs:
         pip install .
     - name: Run tests
       run: |
-        py.test -vv --cov=injector --cov-branch --cov-report html --cov-report term
+        # Run via `python -m pytest` (not `py.test`) so the working directory is on
+        # sys.path and coverage measures the local `injector/` rather than the copy
+        # installed in site-packages. Otherwise coverage reports 0%.
+        # See https://github.com/pytest-dev/pytest-cov/issues/98
+        python -m pytest -vv --cov=injector --cov-branch --cov-report html --cov-report term
         if which mypy; then mypy injector ; fi
         if which black; then black --check . ; fi
         check-manifest