ci: add PR quality and coverage gates

.gitea/workflows/ci.yml

@@ -1,13 +1,17 @@
 name: CI
 
 on:
-  push:
-    branches: [main]
   pull_request:
+    branches: [main]
+
+concurrency:
+  group: ci-${{ gitea.event_name }}-${{ gitea.ref }}
+  cancel-in-progress: true
 
 jobs:
   test:
     runs-on: ubuntu-latest
+    timeout-minutes: 20
     services:
       mysql:
         image: mysql:8.0.35
@@ -45,6 +49,8 @@ jobs:
             --timeout 120 \
             --retries 5 \
             -r requirements-dev.txt
+      - name: Ruff checks
+        run: .venv-ci/bin/ruff check backend scripts
       - name: Check migrations
         working-directory: backend
         run: ../.venv-ci/bin/python manage.py makemigrations --check --dry-run
@@ -54,8 +60,14 @@ jobs:
       - name: ASGI import check
         working-directory: backend
         run: ../.venv-ci/bin/python -c "from config.asgi import application; print(type(application).__name__)"
-      - name: Unit tests
-        run: .venv-ci/bin/python -m pytest -q
+      - name: SQLite tests and coverage
+        run: |
+          .venv-ci/bin/python -m pytest -q \
+            --cov=backend \
+            --cov-config=.coveragerc \
+            --cov-report=term \
+            --cov-report=xml:coverage.xml \
+            --cov-fail-under=75
       - name: MySQL migrations and tests
         env:
           DATABASE_URL: mysql://root:ci-root-password@mysql:3306/hulumath