add unittest workflow

.github/workflows/unittests.yaml

@@ -0,0 +1,27 @@
+on: [ push, pull_request ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Setup Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.9
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install -r requirements.txt
+          python -m pip install pytest
+      - name: Test with coverage/pytest
+        run: |
+          coverage run -m pytest
+      - name: Coveralls
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          pip install --upgrade coveralls
+          coveralls --service=github