fix packaging and imports and introduce tests with pytest.

still issues with celery worker.

.github/workflows/pytest.yml

@@ -0,0 +1,28 @@
+name: Run python tests with pytest
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.9", "3.10", "3.11"]
+
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install pytest
+          cd application
+          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+      - name: Test with pytest
+        run: |
+          cd application
+          pytest