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openspec/changes/enterprise-testing-visual-regression/specs/testing-e2e/spec.md

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+## ADDED Requirements
+
+### Requirement: `configureVisualRegression` factory
+
+The `@suaveplan/testing-e2e` package SHALL export `configureVisualRegression(config?)` returning a `PlaywrightTestConfig` fragment with `expect.toHaveScreenshot.maxDiffPixelRatio` defaulted to `0.005`, `expect.toHaveScreenshot.animations` defaulted to `'disabled'`, `expect.toHaveScreenshot.caret` defaulted to `'hide'`, and `use.viewport` defaulted to `{ width: 1280, height: 720 }`. Caller-supplied values MUST take precedence over defaults.
+
+#### Scenario: Defaults emitted
+
+- **WHEN** `configureVisualRegression()` is called with no arguments
+- **THEN** the returned fragment contains `expect.toHaveScreenshot.maxDiffPixelRatio === 0.005` AND `expect.toHaveScreenshot.animations === 'disabled'` AND `use.viewport.width === 1280`
+
+#### Scenario: Caller override wins
+
+- **WHEN** `configureVisualRegression({ expect: { toHaveScreenshot: { maxDiffPixelRatio: 0.001 } } })` is called
+- **THEN** the returned fragment has `expect.toHaveScreenshot.maxDiffPixelRatio === 0.001`
+
+### Requirement: `prepareForVisual` determinism harness
+
+The package SHALL export `prepareForVisual(page)` which MUST: disable animations via `page.emulateMedia({ reducedMotion: 'reduce' })`, wait for `page.waitForLoadState('networkidle')`, await `document.fonts.ready` inside the page context, and assert the active viewport matches the configured visual viewport. Failure to reach font readiness within `timeoutMs` MUST throw `VisualRegressionError` with `code === 'TESTING_E2E.VISUAL.FONTS_NOT_READY'`.
+
+#### Scenario: Determinism levers applied
+
+- **WHEN** `prepareForVisual(page)` resolves successfully
+- **THEN** `prefers-reduced-motion` is `'reduce'` AND `document.fonts.status === 'loaded'` AND the page has reached `networkidle`
+
+#### Scenario: Font timeout
+
+- **WHEN** `document.fonts.ready` does not resolve within `timeoutMs`
+- **THEN** the call throws `VisualRegressionError` with `code === 'TESTING_E2E.VISUAL.FONTS_NOT_READY'`
+
+#### Scenario: Viewport mismatch
+
+- **WHEN** the page viewport differs from the configured visual viewport at capture time
+- **THEN** the call throws `VisualRegressionError` with `code === 'TESTING_E2E.VISUAL.VIEWPORT_MISMATCH'`
+
+### Requirement: Per-OS baseline storage
+
+Visual baselines SHALL be stored under `apps/<app>/e2e/__snapshots__/<platform>/<spec>/<test>.png` where `<platform>` is one of `linux`, `darwin`, `win32`. A run on a platform with no baseline directory MUST NOT pass implicitly — it MUST throw `VisualRegressionError` with `code === 'TESTING_E2E.VISUAL.BASELINE_MISSING'` unless `--update-snapshots` is in effect.
+
+#### Scenario: Missing baseline fails
+
+- **WHEN** an e2e spec calls `expect(page).toHaveScreenshot()` on a platform with no baseline directory and `--update-snapshots` is NOT set
+- **THEN** the call throws `VisualRegressionError` with `code === 'TESTING_E2E.VISUAL.BASELINE_MISSING'`
+
+#### Scenario: Pixel diff exceeded
+
+- **WHEN** a comparison exceeds the configured `maxDiffPixelRatio`
+- **THEN** the call throws `VisualRegressionError` with `code === 'TESTING_E2E.VISUAL.PIXEL_DIFF_EXCEEDED'` whose `context` contains `{ baselinePath, actualPath, diffPath, pixelRatio }`
+
+### Requirement: Baseline-update workflow discipline
+
+Updates to committed baselines SHALL only occur via runs invoked with `--update-snapshots` AND MUST land in a dedicated commit prefixed `chore(visual): refresh baselines` separate from any feature or fix commit.
+
+#### Scenario: Baseline refresh commit isolated
+
+- **WHEN** baselines are updated
+- **THEN** the resulting commit contains only `__snapshots__/` changes AND its message starts with `chore(visual): refresh baselines`
+
+### Requirement: Per-spec visual invariant
+
+Every page-level Playwright spec under `apps/<app>/e2e/` that asserts rendered DOM SHALL also call `expect(page).toHaveScreenshot()` after `prepareForVisual(page)` resolves. Specs that exclusively test API endpoints (no DOM render) are exempt.
+
+#### Scenario: Page-level spec includes screenshot
+
+- **WHEN** a spec navigates to a route, runs `prepareForVisual(page)`, and asserts rendered DOM
+- **THEN** the spec also calls `expect(page).toHaveScreenshot()` before completing
+
+### Requirement: Structured error codes
+
+All errors thrown from the visual helpers SHALL be subclasses of `TestingE2eError` carrying `{ code, cause?, context? }` and SHALL match the regex `^TESTING_E2E\.VISUAL\.[A-Z_]+$`. Defined codes are `TESTING_E2E.VISUAL.PIXEL_DIFF_EXCEEDED`, `TESTING_E2E.VISUAL.BASELINE_MISSING`, `TESTING_E2E.VISUAL.FONTS_NOT_READY`, `TESTING_E2E.VISUAL.VIEWPORT_MISMATCH`.
+
+#### Scenario: Coded error
+
+- **WHEN** any visual helper throws
+- **THEN** the thrown value `instanceof TestingE2eError` is true AND `err.code` matches the regex
+
+### Requirement: Coverage gate at 100%
+
+Istanbul statement, branch, function, and line coverage across `packages/testing/testing-e2e/src/visual/` (excluding `*.bench.ts`, `*.schemas.ts`, barrel `index.ts`) MUST be 100% on every dimension. The pre-publish gate hard-fails below 100%.
+
+#### Scenario: Coverage gate enforces 100%
+
+- **WHEN** `bunx turbo test:coverage --filter=@suaveplan/testing-e2e` runs
+- **THEN** statements, branches, functions, and lines coverage all equal 100%