Add coverage run to drone

.drone.yml

@@ -8,7 +8,22 @@ name: run_tests
 
 steps:
   # Run tests against Python/Flask engine backend (with pytest)
-  - name: django_tests
+  - name: coverage
+    image: python:3.10.4
+    commands:
+      # Install dependencies
+      - cp vrobbler.conf.example vrobbler.conf
+      - pip install poetry
+      - poetry install
+      # Start with a fresh database (which is already running as a service from Drone)
+      - poetry run pytest --cov-report --cov=vrobbler tests
+    environment:
+      VROBBLER_DATABASE_URL: sqlite:///test.db
+    volumes:
+      # Mount pip cache from host
+      - name: pip_cache
+        path: /root/.cache/pip
+  - name: pytest
     image: python:3.10.4
     commands:
       # Install dependencies