e2e

---
name: e2e
description: Use when running e2e tests, debugging test failures, or fixing flaky tests. Covers failure taxonomy, fix rules, and workflow. Never changes source code logic or API without spec backing.
license: Apache-2.0
---

# 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**B. Outdated** (test no longer matches implementation)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**Outdated fixes:**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- If no spec exists, ask the user: bug or outdated test?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

```bash
# Playwright
yarn playwright test --reporter=line

# Or project-specific
yarn test:e2e
```

Parse failures into:

| Test | File | Error | Category |
|---|---|---|---|
| `login flow` | `auth.spec.ts:42` | timeout waiting for selector | TBD |

### 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.