sakthivel-p-cse/codex/deflake-e2e

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.ts or e2e-tests/main.spec.ts). If not provided, will prompt to deflake the entire test suite.

Instructions

1. Check if specific tests are provided:

If $ARGUMENTS is 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.

1. Install dependencies:

`` npm install ``

1. Build the app binary:

`` npm run build ``

IMPORTANT: 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 of e2e-tests/), you MUST re-run npm run build before running E2E tests again, otherwise you'll be testing the old version.

1. 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=10 ``

IMPORTANT: PLAYWRIGHT_RETRIES=0 is required to disable automatic retries. Without it, CI environments (where CI=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

1. 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.ts ``

Analyze 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

1. Fix the flaky test:

Common fixes following Playwright best practices:

• 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)

IMPORTANT: Do NOT change any application code. Assume the application code is correct. Only modify test files and snapshot baselines.

1. 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 ``

1. 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=10 ``

The test should pass all 10 runs consistently.

1. 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