add coverage

.github/workflows/ci-build.yml

@@ -26,7 +26,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install --upgrade flake8 pytest pycodestyle
+          pip install --upgrade flake8 pytest pycodestyle pytest-cov
           if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
       - name: Lint with flake8
         run: |