addendum

.github/workflows/pytest.yml

@@ -29,6 +29,7 @@ jobs:
         python -m pip install --upgrade pip
         python -m pip install flake8 pytest pytest-doctestplus pytest-cov
         # if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+        pip install .
     - name: Lint with flake8
       run: |
         # stop the build if there are Python syntax errors or undefined names