Add pytest

Author: borkweb

.github/workflows/tests.yml

@@ -26,7 +26,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          python -m pip install --only-binary=wheel setuptools twine
+          python -m pip install --only-binary=wheel setuptools twine pytest
           python -m pip install -e ".[test]"
 
       - name: Unit tests