fix pytest plugins

Author: penguinolog

.github/workflows/pythonpackage.yml

@@ -22,7 +22,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip wheel
         pip install -r CI_REQUIREMENTS.txt
-        pip install --upgrade asynctest mock pytest pytest-mock pytest-asyncio pytest-sugar
+        pip install --upgrade asynctest mock pytest pytest-mock pytest-asyncio pytest-sugar pytest-cov
     - name: Build package and install develop
       run: |
         python setup.py develop -v