ci: add mailpit tests to CI

.github/workflows/build-latest.yml

@@ -21,6 +21,25 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
+      - name: Set up Python environment
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+          cache: 'pip' # caching pip dependencies
+
+      - name: Start test containers
+        run: docker compose -f test/docker-compose.yml up -d --build
+
+      - name: Install test environment
+        run: pip install -r test/requirements.txt
+
+      - name: Run tests
+        run: pytest -vv test/test_mailpit.py
+
+      - name: Stop test containers
+        if: always()
+        run: docker compose -f test/docker-compose.yml down --volumes
+
       - name: Login to DockerHub
         uses: docker/login-action@v3
         with: