E2E Testing

Failure Taxonomy

Every e2e failure is exactly one of:

A. Flaky (test infrastructure issue)

• Race conditions, timing-dependent assertions, stale selectors, missing waits
• Symptom: passes on retry, fails intermittently

B. Outdated (test no longer matches implementation)

• Test asserts old behavior that was intentionally changed; selectors reference removed elements
• Symptom: consistent failure, app works correctly

C. Bug (implementation doesn't match spec)

• Test correctly asserts spec'd behavior, code is wrong
• Only classify as bug when a spec exists to validate against
• If no spec exists, classify as "unverified failure" and report to the user

Fix Rules by Category

Flaky fixes:

• Replace waitForTimeout with auto-waiting locators
• Replace brittle CSS selectors with getByRole/getByLabel/getByTestId
• Fix race conditions with expect() web-first assertions
• Fix mock/route setup ordering (before navigation)
• Never add arbitrary delays - fix the underlying wait
• Never add retry loops around assertions - use the framework's built-in retry

Outdated fixes:

• Update test assertions to match current (correct) behavior
• Update selectors to match current DOM/API
• Never change source code - the implementation is correct, the test is stale

Bug fixes:

• Quote the spec section that defines expected behavior
• Fix the source code to match the spec
• Unit tests MUST exist before the fix is complete — write them first if missing (TDD)
• Never change e2e assertions to match buggy code
• Never change API contracts or interfaces without spec backing
• If no spec exists, ask the user: bug or outdated test?

Source Code Boundary

E2e test fixes must not change application logic, API contracts, database schemas, or configuration defaults. The only exception: bug fixes where a spec explicitly defines the correct behavior and unit tests cover the fix.

Workflow

Step 1: Discover Test Infrastructure

1. Find e2e config: playwright.config.ts, vitest.config.ts, or project-specific setup
2. Read package.json for the canonical e2e command
3. Check if dev server or Tilt environment is required and running
4. Find spec files: *.spec.md, docs/*.spec.md - source of truth for bug decisions

Step 2: Run Tests

# Playwright
yarn playwright test --reporter=line

# Or project-specific
yarn test:e2e

Parse failures into:

Step 3: Categorize

For each failure: read the test file, read the source code it exercises, check for a corresponding spec file, assign category (flaky / outdated / bug / unverified).

Step 4: Fix by Category

Apply fixes in order: flaky first (unblocks other tests), then outdated, then bug.

Step 5: Re-run and Report

## E2E Results

**Run**: `yarn test:e2e` on <date>
**Result**: X/Y passed

### Fixed
- FLAKY: `auth.spec.ts:42` - replaced waitForTimeout with getByRole wait
- OUTDATED: `profile.spec.ts:88` - updated selector after header redesign
- BUG: `transfer.spec.ts:120` - fixed amount validation per SPEC.md#transfers

### Remaining Failures
- UNVERIFIED: `settings.spec.ts:55` - no spec, needs user decision

### Unit Tests Added
- `src/transfer.test.ts` - amount validation edge cases (covers BUG fix)

See testing-best-practices for async handling, flake classification, and preflight check patterns.