Fix Failing or Flaky Tests

Diagnose and fix a Playwright test that fails or passes intermittently using a systematic taxonomy.

Input

$ARGUMENTS

• A test file path:

  e2e/login.spec.ts

• A test name: ""should redirect after login"`
• A description:

  "the checkout test fails in CI but passes locally"

Steps

1. Reproduce the Failure

Run the test to capture the error:

npx playwright test <file> --reporter=list

If the test passes, it's likely flaky. Run burn-in:

npx playwright test <file> --repeat-each=10 --reporter=list

If it still passes, try with parallel workers:

npx playwright test --fully-parallel --workers=4 --repeat-each=5

2. Capture Trace

Run with full tracing:

npx playwright test <file> --trace=on --retries=0

Read the trace output. Use

/debug

3. Categorize the Failure

Load

flaky-taxonomy.md

Every failing test falls into one of four categories:

--repeat-each=20

--workers=1 --grep "test name"

4. Apply Targeted Fix

Timing/Async:

• Replace

  waitForTimeout()

  with web-first assertions
• Add

  await

  to missing Playwright calls
• Wait for specific network responses before asserting
• Use

  toBeVisible()

  before interacting with elements

Test Isolation:

• Remove shared mutable state between tests
• Create test data per-test via API or fixtures
• Use unique identifiers (timestamps, random strings) for test data
• Check for database state leaks

Environment:

• Match viewport sizes between local and CI
• Account for font rendering differences in screenshots
• Use

  docker

  locally to match CI environment
• Check for timezone-dependent assertions

Infrastructure:

• Increase timeout for slow CI runners
• Add retries in CI config (

  retries: 2

  )
• Check for browser OOM (reduce parallel workers)
• Ensure browser dependencies are installed

5. Verify the Fix

Run the test 10 times to confirm stability:

npx playwright test <file> --repeat-each=10 --reporter=list

All 10 must pass. If any fail, go back to step 3.

6. Prevent Recurrence

Suggest:

• Add to CI with

  retries: 2

  if not already
• Enable

  trace: 'on-first-retry'

  in config
• Add the fix pattern to project's test conventions doc

Output

• Root cause category and specific issue
• The fix applied (with diff)
• Verification result (10/10 passes)
• Prevention recommendation