Senior
How do you find flaky tests and how do you fix them?
sobes.tech AI
Answer from AI
Finding flaky tests:
- Analyzing logs and test results: flaky tests appear as unstable — sometimes passing, sometimes failing without changes in the code.
- Running tests multiple times (e.g., 10-20 times in a row) to identify instability.
- Using tools and plugins that track unstable tests (e.g., Flaky Test Detector).
Fixing flaky tests:
- Isolate the test: ensure the test does not depend on external factors (environment state, time, random data).
- Stabilize data: use mock data or fixtures instead of real requests.
- Synchronization: add waits (wait, await) for asynchronous operations so the test does not run prematurely.
- Avoid dependencies on test execution order: each test should be independent.
- Refactor the test: simplify logic, remove randomness.
Example: if a test fails because an element appears on the page with a delay, add an explicit wait for the element to appear instead of relying on a fixed wait time.
Ultimately, flaky tests are identified through repeated runs and analysis, and eliminated by increasing the stability and predictability of the test environment and the test itself.