Install more dependencies

.github/workflows/python-app.yml

@@ -27,7 +27,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install flake8 pytest
-        pip install .
+        pip install -e .[test]
     - name: Lint with flake8
       run: |
         # stop the build if there are Python syntax errors or undefined names