Run pre-commit before merging

.github/workflows/test.yaml

@@ -8,9 +8,31 @@ permissions:
   contents: read
 
 jobs:
+  tests:
+    name: Python tests
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Set up Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: '3.11'
+          cache: pip
+      - name: Install dependencies
+        run: |
+          pip install pre-commit
+      - name: Setup pre-commit cache
+        uses: actions/cache@v3
+        with:
+          path: ~/.cache/pre-commit
+          key: pre-commit-3|${{ env.pythonLocation }}|${{ hashFiles('.pre-commit-config.yaml') }}
+      - name: Check pre-commit
+        run: pre-commit run --show-diff-on-failure --color=always --all-files
   auto_merge:
     name: Auto merge
     runs-on: ubuntu-latest
+    needs: tests
     permissions:
       pull-requests: write
       contents: write