Fixed test layout and added pipeline step to actually run tests

.github/workflows/run_tests.yml

@@ -0,0 +1,22 @@
+---
+name: Pytest code testing
+
+on: 
+  workflow_call
+
+jobs:
+  test_code:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python
+      uses: actions/setup-python@v5
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install pytest pytest-mock
+        pip install -r requirements.txt
+    - name: Analysing the code with pylint
+      run: |
+        cp config.py.example config.py
+        pytest tests