Combining Docker containers with automated testing improves testing efficiency and consistency. Testing scenarios: 1) unit testing: run test code in containers; 2) integration testing: use Docker Compose to start dependency services; 3) end-to-end testing: run browser tests (Selenium) in containers; 4) performance testing: run stress testing tools (JMeter, Locust) in containers. Best practices: use multi-stage builds to build test images, use volumes to share test results, configure test environment variables, implement test report generation, integrate into CI/CD workflows. Advantages: environment consistency, fast startup and cleanup, parallel test execution.