Fix unit tests

.github/workflows/ci.yml

@@ -0,0 +1,32 @@
+name: ci
+
+on: [push, pull_request]
+
+jobs:
+
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.8", "3.9", "3.10", "3.11"]
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Install poetry
+      run: pipx install poetry
+
+    - name: Install python dependencies
+      run: |
+        poetry env use ${{ matrix.python-version }}
+        poetry install --with dev
+
+    - name: Run unit tests
+      run: |
+        poetry run python -m unittest -v tests
+