Flaky Tests
What are Flaky Tests?
Flaky tests are defined as tests that return both passes and failures despite no changes to the code or the test itself.
Common Causes
- Asynchronous operations
- Time dependencies
- Shared state between tests
- Race conditions
- Network reliability
- Resource constraints
Impact on Development
- Reduced confidence in test suite
- Increased build times
- Developer frustration
- Delayed releases
- Technical debt
Solutions
Problem | Solution |
---|---|
Async Issues | Implement proper wait mechanisms |
Timing Problems | Use deterministic time controls |
Shared State | Isolate test environments |
Race Conditions | Implement proper synchronization |
Best Practices
- Isolate tests properly
- Use deterministic data
- Implement retry mechanisms
- Monitor test execution times
- Document known flaky tests
- Set up proper test environments
Detection Strategies
- Run tests multiple times
- Use test analytics tools
- Monitor test execution history
- Implement logging for failures
Prevention Tips
- Write deterministic tests
- Avoid external dependencies when possible
- Use proper mocking techniques
- Implement proper cleanup routines
- Regular test maintenance