Deflake E2E Tests
Identify and fix flaky E2E tests by running them repeatedly and investigating failures.
Arguments
$ARGUMENTS: (Optional) Specific E2E test file(s) to deflake (e.g.,main.spec.tsore2e-tests/main.spec.ts). If not provided, will prompt to deflake the entire test suite.
Instructions
- Check if specific tests are provided: If
$ARGUMENTSis empty or not provided, ask the user: "No specific tests provided. Do you want to deflake the entire E2E test suite? This can take a very long time as each test will be run 10 times." Wait for user confirmation before proceeding. If they decline, ask them to provide specific test files. - Install dependencies:
npm install - Build the app binary:
npm run buildIMPORTANT: This step is required before running E2E tests. E2E tests run against the built binary. If you make any changes to application code (anything outside ofe2e-tests/), you MUST re-runnpm run buildbefore running E2E tests again, otherwise you'll be testing the old version. - Run tests repeatedly to detect flakiness: For each test file, run it 10 times:
PLAYWRIGHT_RETRIES=0 PLAYWRIGHT_HTML_OPEN=never npm run e2e -- e2e-tests/<testfile>.spec.ts --repeat-each=10IMPORTANT:PLAYWRIGHT_RETRIES=0is required to disable automatic retries. Without it, CI environments (whereCI=true) default to 2 retries, causing flaky tests to pass on retry and be incorrectly skipped as "not flaky." Notes:
- If $ARGUMENTS is provided without the e2e-tests/ prefix, add it - If $ARGUMENTS is provided without the .spec.ts suffix, add it - A test is considered flaky if it fails at least once out of 10 runs
- For each flaky test, investigate with debug logs: Run the failing test with Playwright browser debugging enabled:
DEBUG=pw:browser PLAYWRIGHT_RETRIES=0 PLAYWRIGHT_HTML_OPEN=never npm run e2e -- e2e-tests/<testfile>.spec.tsAnalyze the debug output to understand:
- Timing issues (race conditions, elements not ready) - Animation/transition interference - Network timing variability - State leaking between tests - Snapshot comparison differences
- Fix the flaky test: Common fixes following Playwright best practices: IMPORTANT: Do NOT change any application code. Assume the application code is correct. Only modify test files and snapshot baselines.
- Use await expect(locator).toBeVisible() before interacting with elements - Use await page.waitForLoadState('networkidle') for network-dependent tests - Use stable selectors (data-testid, role, text) instead of fragile CSS selectors - Add explicit waits for animations: await page.waitForTimeout(300) (use sparingly) - Use await expect(locator).toHaveScreenshot() options like maxDiffPixelRatio for visual tests - Ensure proper test isolation (clean state before/after tests)
- Update snapshot baselines if needed: If the flakiness is due to legitimate visual differences:
PLAYWRIGHT_RETRIES=0 PLAYWRIGHT_HTML_OPEN=never npm run e2e -- e2e-tests/<testfile>.spec.ts --update-snapshots - Verify the fix: Re-run the test 10 times to confirm it's no longer flaky:
PLAYWRIGHT_RETRIES=0 PLAYWRIGHT_HTML_OPEN=never npm run e2e -- e2e-tests/<testfile>.spec.ts --repeat-each=10The test should pass all 10 runs consistently. - Summarize results: Report to the user:
- Which tests were identified as flaky - What was causing the flakiness - What fixes were applied - Verification results (all 10 runs passing) - Any tests that could not be fixed and need further investigation