Feature 15: Recipe Detail and Kitchen Reading Mode (#162)

Co-authored-by: orchestrator-agent <20+orchestrator-agent@code.cubecraftcreations.com>

web/src/dinners/KitchenReading.test.tsx

@@ -0,0 +1,604 @@
+import { act, fireEvent, render, screen, waitFor, within } from '@testing-library/react'
+import { createMemoryRouter, RouterProvider } from 'react-router'
+import { afterEach, beforeEach, describe, expect, it, vi, type Mock } from 'vitest'
+import { ApiProviders, HOUSEHOLD_SETTINGS } from '../test/ApiProviders.tsx'
+import { declaredStyle } from '../test/cssRules.ts'
+import { errorResponse, jsonResponse } from '../test/fetchStub.ts'
+import { mockViewport } from '../test/matchMedia.ts'
+import { DinnerDetailPage } from './DinnerDetailPage.tsx'
+import { TEXT_SIZE_KEY } from './textSize.ts'
+
+const DINNER = '/api/v1/dinners/d1'
+const SETTINGS = '/api/v1/settings/household'
+const THIS_WEEK = '/api/v1/plans/2026-10-05'
+const NEXT_WEEK = '/api/v1/plans/2026-10-12'
+
+// detail is the Korean beef bowls, a Quest-log Side quest, as GET
+// /api/v1/dinners/{id} sends it.
+function detail(overrides: Record<string, unknown> = {}) {
+  return {
+    id: 'd1',
+    name: 'Korean beef bowls',
+    status: 'quest_log',
+    origin: 'suggested',
+    method: 'stovetop',
+    minutes_total: 30,
+    difficulty: 'easy',
+    cuisine: 'korean',
+    is_favorite: false,
+    photo_urls: null,
+    ingredients: [
+      { name: 'Ground beef', qty: '1', unit: 'lb', note: null, raw_text: '1 lb ground beef' },
+      { name: 'Jasmine rice', qty: '2', unit: 'cups', note: null, raw_text: '2 cups jasmine rice' },
+      { name: 'Green onions', qty: '1', unit: 'bunch', note: 'sliced', raw_text: '1 bunch green onions, sliced' },
+    ],
+    steps: [
+      'Rinse the rice and start it cooking.',
+      'Brown the beef with the garlic and ginger.',
+      'Stir in the sauce and simmer until glossy.',
+    ],
+    source: null,
+    grounding_status: 'grounded',
+    grounding_error: null,
+    why_picked: 'close cousin of your Beef tacos.',
+    ...overrides,
+  }
+}
+
+// planBody is a week's plan as GET /api/v1/plans/{weekStart} sends it: p0 to
+// p6, except the bowls (d1) on each day of bowlsOn, counting from Monday = 0.
+function planBody(weekStart: string, ...bowlsOn: number[]) {
+  const start = new Date(`${weekStart}T00:00:00Z`).getTime()
+  return {
+    id: `plan-${weekStart}`,
+    week_start: weekStart,
+    status: 'draft',
+    ai_note: null,
+    calendar_synced_at: null,
+    days: Array.from({ length: 7 }, (_, i) => ({
+      date: new Date(start + i * 86_400_000).toISOString().slice(0, 10),
+      dinner:
+        bowlsOn.includes(i)
+          ? { id: 'd1', name: 'Korean beef bowls', photo: null, minutes: 30, method: 'stovetop' }
+          : { id: `p${i}`, name: `Dinner ${i}`, photo: null, minutes: 30, method: 'stovetop' },
+      is_new: bowlsOn.includes(i),
+      start_by: null,
+    })),
+  }
+}
+
+// serve answers the screen's reads: the dinner, the household settings and
+// both weeks' plans, unless responses says otherwise.
+function serve(responses: Record<string, () => Response> = {}): Mock<typeof fetch> {
+  const all: Record<string, () => Response> = {
+    [DINNER]: () => jsonResponse(200, detail()),
+    [SETTINGS]: () => jsonResponse(200, HOUSEHOLD_SETTINGS),
+    [THIS_WEEK]: () => jsonResponse(200, planBody('2026-10-05', 5)),
+    [NEXT_WEEK]: () => errorResponse(404, 'not_found'),
+    ...responses,
+  }
+  const fetchMock = vi.fn<typeof fetch>((input, init) => {
+    const path = String(input)
+    const respond = Object.hasOwn(all, path) ? all[path] : undefined
+    if (respond === undefined) throw new Error(`unexpected fetch: ${init?.method ?? 'GET'} ${path}`)
+    return Promise.resolve(respond())
+  })
+  vi.stubGlobal('fetch', fetchMock)
+  return fetchMock
+}
+
+function reads(fetchMock: Mock<typeof fetch>, path: string) {
+  return fetchMock.mock.calls.filter(([input]) => String(input) === path).length
+}
+
+// renderPage renders the bowls' detail screen and waits for its title.
+async function renderPage() {
+  const router = createMemoryRouter([{ path: '/dinner/:id', element: <DinnerDetailPage /> }], {
+    initialEntries: ['/dinner/d1'],
+  })
+  const view = render(
+    <ApiProviders>
+      <RouterProvider router={router} />
+    </ApiProviders>,
+  )
+  await screen.findByRole('heading', { level: 1, name: 'Korean beef bowls' })
+  return view
+}
+
+function steps() {
+  return within(screen.getByRole('region', { name: 'Steps' })).getAllByRole('listitem')
+}
+
+// currentStep is the text of the step marked current.
+function currentStep() {
+  const current = steps().filter((step) => step.getAttribute('aria-current') === 'step')
+  expect(current).toHaveLength(1)
+  return current[0]!.textContent
+}
+
+// FakeSentinel is a WakeLockSentinel as far as the screen uses one.
+type FakeSentinel = EventTarget & { released: boolean; release: Mock<() => Promise<void>> }
+
+// letGo releases a lock as the browser does, telling its listeners so.
+function letGo(sentinel: FakeSentinel) {
+  if (sentinel.released) return
+  sentinel.released = true
+  sentinel.dispatchEvent(new Event('release'))
+}
+
+// stubWakeLock gives jsdom, which has none, a Screen Wake Lock. Each request
+// is granted at once, or, given hold, only when the test calls grant.
+function stubWakeLock({ hold = false } = {}) {
+  const sentinels: FakeSentinel[] = []
+  const pending: (() => void)[] = []
+  const request = vi.fn((type: string) => {
+    expect(type).toBe('screen')
+    const sentinel: FakeSentinel = Object.assign(new EventTarget(), {
+      released: false,
+      release: vi.fn(() => {
+        letGo(sentinel)
+        return Promise.resolve()
+      }),
+    })
+    sentinels.push(sentinel)
+    if (!hold) return Promise.resolve(sentinel)
+    return new Promise<FakeSentinel>((resolve) => pending.push(() => resolve(sentinel)))
+  })
+  Object.defineProperty(navigator, 'wakeLock', { configurable: true, value: { request } })
+  return { request, sentinels, grant: () => pending.shift()!() }
+}
+
+// setVisibility shows or hides the page as the browser would, telling the
+// page so.
+function setVisibility(state: DocumentVisibilityState) {
+  Object.defineProperty(document, 'visibilityState', { configurable: true, get: () => state })
+  document.dispatchEvent(new Event('visibilitychange'))
+}
+
+beforeEach(() => {
+  mockViewport(1180)
+  // Wednesday Oct 7, noon in New York.
+  vi.useFakeTimers({ toFake: ['Date'] })
+  vi.setSystemTime(new Date('2026-10-07T16:00:00Z'))
+})
+
+afterEach(() => {
+  vi.useRealTimers()
+  Reflect.deleteProperty(window, 'matchMedia')
+  Reflect.deleteProperty(navigator, 'wakeLock')
+  Reflect.deleteProperty(document, 'visibilityState')
+  vi.unstubAllGlobals()
+})
+
+describe('Kitchen reading mode', () => {
+  it('is the tablet layout of the same route: header with back, title, Keep screen on and text size', async () => {
+    stubWakeLock()
+    serve()
+    await renderPage()
+
+    const title = screen.getByRole('heading', { level: 1, name: 'Korean beef bowls' })
+    expect(declaredStyle(title).fontSize).toBe('36px')
+    expect(screen.getByRole('button', { name: 'Back' })).toBeInTheDocument()
+    // Not the phone's sheet: no photo hero tags.
+    expect(screen.queryByText('Easy')).not.toBeInTheDocument()
+
+    const keepOn = screen.getByRole('switch', { name: 'Keep screen on' })
+    expect(keepOn).toHaveAttribute('aria-checked', 'false')
+    fireEvent.click(keepOn)
+    expect(keepOn).toHaveAttribute('aria-checked', 'true')
+
+    const sizes = screen.getByRole('radiogroup', { name: 'Text size' })
+    expect(within(sizes).getAllByRole('radio').map((radio) => radio.getAttribute('aria-label'))).toEqual([
+      'Small text',
+      'Medium text',
+      'Large text',
+    ])
+    expect(within(sizes).getByRole('radio', { name: 'Medium text' })).toHaveAttribute('aria-checked', 'true')
+
+    expect(declaredStyle(screen.getByRole('region', { name: 'Ingredients' }).parentElement!).gridTemplateColumns).toBe(
+      '400px minmax(0, 1fr)',
+    )
+    expect(screen.getByText(/close cousin of your Beef tacos/)).toHaveTextContent('Why it was picked: close cousin')
+  })
+
+  describe('kicker', () => {
+    it('names the day the plan has the dinner on, and Side quest', async () => {
+      serve()
+      await renderPage()
+      expect(await screen.findByText('Saturday, Oct 10 · Side quest')).toBeInTheDocument()
+    })
+
+    it("names a day of next week's plan, and Regular, for a Regular", async () => {
+      serve({
+        [DINNER]: () => jsonResponse(200, detail({ status: 'regular', origin: 'regular' })),
+        [THIS_WEEK]: () => jsonResponse(200, planBody('2026-10-05')),
+        [NEXT_WEEK]: () => jsonResponse(200, planBody('2026-10-12', 0)),
+      })
+      await renderPage()
+      expect(await screen.findByText('Monday, Oct 12 · Regular')).toBeInTheDocument()
+    })
+
+    it("names a day of this week's plan already past when that is the only day", async () => {
+      // Today is Wednesday; the bowls were on Monday, and are on no day of next week.
+      serve({
+        [THIS_WEEK]: () => jsonResponse(200, planBody('2026-10-05', 0)),
+        [NEXT_WEEK]: () => jsonResponse(200, planBody('2026-10-12')),
+      })
+      await renderPage()
+      expect(await screen.findByText('Monday, Oct 5 · Side quest')).toBeInTheDocument()
+    })
+
+    it('names the first day from today on over a day already past', async () => {
+      serve({ [THIS_WEEK]: () => jsonResponse(200, planBody('2026-10-05', 0, 1, 4, 6)) })
+      await renderPage()
+      expect(await screen.findByText('Friday, Oct 9 · Side quest')).toBeInTheDocument()
+      expect(screen.queryByText(/Monday|Tuesday|Sunday/)).not.toBeInTheDocument()
+    })
+
+    it('names the latest day already past when every day is past', async () => {
+      serve({ [THIS_WEEK]: () => jsonResponse(200, planBody('2026-10-05', 0, 1)) })
+      await renderPage()
+      expect(await screen.findByText('Tuesday, Oct 6 · Side quest')).toBeInTheDocument()
+      expect(screen.queryByText(/Monday/)).not.toBeInTheDocument()
+    })
+
+    it('is absent when neither week has a plan', async () => {
+      const fetchMock = serve({ [THIS_WEEK]: () => errorResponse(404, 'not_found') })
+      await renderPage()
+      await waitFor(() => expect(reads(fetchMock, THIS_WEEK)).toBe(1))
+      await waitFor(() => expect(reads(fetchMock, NEXT_WEEK)).toBe(1))
+      await act(async () => {})
+      expect(screen.queryByText(/· Side quest/)).not.toBeInTheDocument()
+      expect(screen.queryByText(/Oct/)).not.toBeInTheDocument()
+    })
+
+    it('says so when the plan cannot be read, with Retry', async () => {
+      let failing = true
+      serve({
+        [THIS_WEEK]: () => (failing ? errorResponse(500, 'internal') : jsonResponse(200, planBody('2026-10-05', 5))),
+      })
+      await renderPage()
+      expect(await screen.findByText(/Couldn't check the plan for this dinner's day/)).toBeInTheDocument()
+
+      failing = false
+      fireEvent.click(screen.getByRole('button', { name: 'Retry' }))
+      expect(await screen.findByText('Saturday, Oct 10 · Side quest')).toBeInTheDocument()
+    })
+  })
+
+  describe('ingredients', () => {
+    it('checks ingredients off with 22 px checkboxes, struck through, counting those set out', async () => {
+      const fetchMock = serve()
+      await renderPage()
+      const card = screen.getByRole('region', { name: 'Ingredients' })
+      expect(within(card).getByText('0 of 3 set out')).toBeInTheDocument()
+
+      const beef = within(card).getByRole('checkbox', { name: 'Ground beef' })
+      expect(declaredStyle(beef).width).toBe('22px')
+      expect(declaredStyle(beef).height).toBe('22px')
+      expect(within(card).getByRole('checkbox', { name: 'Green onions, sliced' })).not.toBeChecked()
+
+      fireEvent.click(beef)
+      expect(beef).toBeChecked()
+      expect(declaredStyle(within(card).getByText('Ground beef')).textDecoration).toBe('line-through')
+      fireEvent.click(within(card).getByRole('checkbox', { name: 'Jasmine rice' }))
+      expect(within(card).getByText('2 of 3 set out')).toBeInTheDocument()
+
+      fireEvent.click(beef)
+      expect(beef).not.toBeChecked()
+      expect(declaredStyle(within(card).getByText('Ground beef')).textDecoration).toBe('')
+      expect(within(card).getByText('1 of 3 set out')).toBeInTheDocument()
+
+      // Local to the screen: nothing is sent.
+      expect(fetchMock.mock.calls.filter(([, init]) => (init?.method ?? 'GET') !== 'GET')).toEqual([])
+    })
+
+    it('starts afresh on the next visit', async () => {
+      serve()
+      const view = await renderPage()
+      fireEvent.click(screen.getByRole('checkbox', { name: 'Ground beef' }))
+      fireEvent.click(screen.getByRole('button', { name: 'Next step' }))
+      view.unmount()
+
+      await renderPage()
+      expect(screen.getByText('0 of 3 set out')).toBeInTheDocument()
+      expect(currentStep()).toBe('1Rinse the rice and start it cooking.')
+    })
+  })
+
+  describe('steps', () => {
+    it('highlights the current step in 22 px text, others 18 px, and moves by Previous and Next step', async () => {
+      serve()
+      await renderPage()
+      const previous = screen.getByRole('button', { name: 'Previous' })
+      const next = screen.getByRole('button', { name: 'Next step' })
+
+      expect(currentStep()).toBe('1Rinse the rice and start it cooking.')
+      expect(previous).toBeDisabled()
+      expect(declaredStyle(steps()[0]!).fontSize).toBe('calc(22px * var(--reading-scale))')
+      expect(declaredStyle(steps()[0]!).background).toBe('var(--color-accent-100)')
+      expect(declaredStyle(steps()[0]!).boxShadow).toBe('inset 0 0 0 2px var(--color-accent-300)')
+      expect(declaredStyle(steps()[1]!).fontSize).toBe('calc(18px * var(--reading-scale))')
+
+      fireEvent.click(next)
+      expect(currentStep()).toBe('2Brown the beef with the garlic and ginger.')
+      // The step done is muted, its number a check.
+      expect(steps()[0]!.textContent).toBe('Rinse the rice and start it cooking.')
+      expect(steps()[0]!.querySelector('svg')).not.toBeNull()
+      expect(declaredStyle(steps()[0]!).color).toBe('var(--color-neutral-600)')
+      expect(declaredStyle(steps()[0]!).fontSize).toBe('calc(18px * var(--reading-scale))')
+
+      fireEvent.click(next)
+      expect(currentStep()).toBe('3Stir in the sauce and simmer until glossy.')
+      expect(next).toBeDisabled()
+      fireEvent.click(next)
+      expect(currentStep()).toBe('3Stir in the sauce and simmer until glossy.')
+
+      fireEvent.click(previous)
+      expect(currentStep()).toBe('2Brown the beef with the garlic and ginger.')
+    })
+
+    it('moves by the ← and → keys, stopping at either end', async () => {
+      serve()
+      await renderPage()
+
+      fireEvent.keyDown(document.body, { key: 'ArrowRight' })
+      expect(currentStep()).toBe('2Brown the beef with the garlic and ginger.')
+      fireEvent.keyDown(document.body, { key: 'ArrowRight' })
+      fireEvent.keyDown(document.body, { key: 'ArrowRight' })
+      expect(currentStep()).toBe('3Stir in the sauce and simmer until glossy.')
+      fireEvent.keyDown(document.body, { key: 'ArrowLeft' })
+      expect(currentStep()).toBe('2Brown the beef with the garlic and ginger.')
+      fireEvent.keyDown(document.body, { key: 'ArrowLeft' })
+      fireEvent.keyDown(document.body, { key: 'ArrowLeft' })
+      expect(currentStep()).toBe('1Rinse the rice and start it cooking.')
+
+      // From a checked ingredient too.
+      const beef = screen.getByRole('checkbox', { name: 'Ground beef' })
+      beef.focus()
+      fireEvent.keyDown(beef, { key: 'ArrowRight' })
+      expect(currentStep()).toBe('2Brown the beef with the garlic and ginger.')
+    })
+
+    it('leaves the keys alone in a text field, with a modifier, or in the text size control', async () => {
+      serve()
+      await renderPage()
+      const field = document.createElement('input')
+      document.body.append(field)
+      field.focus()
+      fireEvent.keyDown(field, { key: 'ArrowRight' })
+      expect(currentStep()).toBe('1Rinse the rice and start it cooking.')
+      field.remove()
+
+      fireEvent.keyDown(document.body, { key: 'ArrowRight', altKey: true })
+      expect(currentStep()).toBe('1Rinse the rice and start it cooking.')
+
+      const medium = screen.getByRole('radio', { name: 'Medium text' })
+      fireEvent.keyDown(medium, { key: 'ArrowRight' })
+      expect(screen.getByRole('radio', { name: 'Large text' })).toHaveAttribute('aria-checked', 'true')
+      expect(currentStep()).toBe('1Rinse the rice and start it cooking.')
+    })
+  })
+
+  describe('text size', () => {
+    it('is remembered on this device', async () => {
+      serve()
+      const view = await renderPage()
+      fireEvent.click(screen.getByRole('radio', { name: 'Large text' }))
+      expect(localStorage.getItem(TEXT_SIZE_KEY)).toBe('large')
+      expect(screen.getByRole('radio', { name: 'Large text' })).toHaveAttribute('aria-checked', 'true')
+      view.unmount()
+
+      await renderPage()
+      expect(screen.getByRole('radio', { name: 'Large text' })).toHaveAttribute('aria-checked', 'true')
+      expect(screen.getByRole('radio', { name: 'Medium text' })).toHaveAttribute('aria-checked', 'false')
+      expect(declaredStyle(screen.getByRole('heading', { level: 1 }).closest('header')!.parentElement!).getPropertyValue('--reading-scale')).toBe(
+        '1.25',
+      )
+    })
+
+    it('says so when the size saved is not one MealQuest saved, until one is chosen', async () => {
+      localStorage.setItem(TEXT_SIZE_KEY, 'huge')
+      serve()
+      await renderPage()
+      expect(screen.getByText(/Could not read the text size chosen on this device/)).toHaveTextContent('"huge"')
+      expect(screen.getByRole('radio', { name: 'Medium text' })).toHaveAttribute('aria-checked', 'true')
+
+      fireEvent.click(screen.getByRole('radio', { name: 'Small text' }))
+      expect(screen.queryByText(/Could not read the text size/)).not.toBeInTheDocument()
+      expect(localStorage.getItem(TEXT_SIZE_KEY)).toBe('small')
+    })
+  })
+
+  describe('source credit', () => {
+    it.each([
+      ['a site and a url', { site_name: 'Serious Eats', url: 'https://www.seriouseats.com/bowls' }, 'Recipe from Serious Eats'],
+      ['only a url', { site_name: null, url: 'https://www.seriouseats.com/bowls' }, 'Recipe from www.seriouseats.com'],
+    ])('links the recipe page in a new tab for %s', async (_, source, name) => {
+      serve({ [DINNER]: () => jsonResponse(200, detail({ source })) })
+      await renderPage()
+      const credit = screen.getByRole('link', { name })
+      expect(credit).toHaveAttribute('href', 'https://www.seriouseats.com/bowls')
+      expect(credit).toHaveAttribute('target', '_blank')
+      expect(credit).toHaveAttribute('rel', 'noopener noreferrer')
+    })
+
+    it.each([
+      ['only a site', { site_name: 'Serious Eats', url: null }, 'Recipe from Serious Eats'],
+      ['neither site nor url', { site_name: null, url: null }, 'Recipe from the web'],
+    ])('is plain text for %s', async (_, source, text) => {
+      serve({ [DINNER]: () => jsonResponse(200, detail({ source })) })
+      await renderPage()
+      expect(screen.getByText(text).closest('a')).toBeNull()
+      expect(screen.queryByRole('link', { name: /Recipe from/ })).not.toBeInTheDocument()
+    })
+
+    it('is absent for a recipe typed in', async () => {
+      serve({ [DINNER]: () => jsonResponse(200, detail({ source: null, grounding_status: 'manual' })) })
+      await renderPage()
+      expect(screen.queryByText(/Recipe from/)).not.toBeInTheDocument()
+    })
+  })
+
+  it('shows what stands in for a recipe not found, with no step buttons', async () => {
+    serve({
+      [DINNER]: () =>
+        jsonResponse(200, detail({ ingredients: [], steps: [], grounding_status: 'failed', grounding_error: 'no_recipe_found' })),
+    })
+    await renderPage()
+    expect(screen.getByRole('link', { name: 'Fix recipe' })).toBeInTheDocument()
+    expect(screen.queryByRole('region', { name: 'Ingredients' })).not.toBeInTheDocument()
+    expect(screen.queryByRole('button', { name: 'Next step' })).not.toBeInTheDocument()
+    expect(screen.getByRole('button', { name: 'Add to this week' })).toBeInTheDocument()
+  })
+
+  describe('Keep screen on', () => {
+    it('holds a screen wake lock while on and releases it when turned off', async () => {
+      const wakeLock = stubWakeLock()
+      serve()
+      await renderPage()
+      const keepOn = screen.getByRole('switch', { name: 'Keep screen on' })
+      expect(keepOn).toBeEnabled()
+      expect(wakeLock.request).not.toHaveBeenCalled()
+
+      fireEvent.click(keepOn)
+      expect(keepOn).toHaveAttribute('aria-checked', 'true')
+      await waitFor(() => expect(wakeLock.request).toHaveBeenCalledTimes(1))
+      expect(wakeLock.sentinels[0]!.release).not.toHaveBeenCalled()
+
+      fireEvent.click(keepOn)
+      expect(keepOn).toHaveAttribute('aria-checked', 'false')
+      expect(wakeLock.sentinels[0]!.release).toHaveBeenCalledTimes(1)
+
+      // On again: a fresh lock.
+      fireEvent.click(keepOn)
+      await waitFor(() => expect(wakeLock.request).toHaveBeenCalledTimes(2))
+      expect(wakeLock.sentinels[1]!.released).toBe(false)
+    })
+
+    it('releases the lock when the screen is left', async () => {
+      const wakeLock = stubWakeLock()
+      serve()
+      const view = await renderPage()
+      fireEvent.click(screen.getByRole('switch', { name: 'Keep screen on' }))
+      await waitFor(() => expect(wakeLock.request).toHaveBeenCalledTimes(1))
+
+      view.unmount()
+      expect(wakeLock.sentinels[0]!.release).toHaveBeenCalledTimes(1)
+    })
+
+    it('releases a lock granted only after the screen was left', async () => {
+      const wakeLock = stubWakeLock({ hold: true })
+      serve()
+      const view = await renderPage()
+      fireEvent.click(screen.getByRole('switch', { name: 'Keep screen on' }))
+      expect(wakeLock.request).toHaveBeenCalledTimes(1)
+
+      view.unmount()
+      await act(async () => wakeLock.grant())
+      expect(wakeLock.sentinels[0]!.release).toHaveBeenCalledTimes(1)
+    })
+
+    it('asks for the lock again when the page is visible again while on, and not while off', async () => {
+      const wakeLock = stubWakeLock()
+      serve()
+      await renderPage()
+      const keepOn = screen.getByRole('switch', { name: 'Keep screen on' })
+      fireEvent.click(keepOn)
+      await waitFor(() => expect(wakeLock.request).toHaveBeenCalledTimes(1))
+
+      // Hidden, the browser lets the lock go; nothing is asked while hidden.
+      act(() => setVisibility('hidden'))
+      act(() => letGo(wakeLock.sentinels[0]!))
+      expect(wakeLock.request).toHaveBeenCalledTimes(1)
+
+      act(() => setVisibility('visible'))
+      await waitFor(() => expect(wakeLock.request).toHaveBeenCalledTimes(2))
+      expect(keepOn).toHaveAttribute('aria-checked', 'true')
+
+      // Visible again with the lock still held: no second lock.
+      act(() => setVisibility('visible'))
+      expect(wakeLock.request).toHaveBeenCalledTimes(2)
+
+      fireEvent.click(keepOn)
+      act(() => setVisibility('hidden'))
+      act(() => setVisibility('visible'))
+      expect(wakeLock.request).toHaveBeenCalledTimes(2)
+    })
+
+    it('asks for the lock again when the browser lets it go while the page is visible', async () => {
+      const wakeLock = stubWakeLock()
+      serve()
+      await renderPage()
+      const keepOn = screen.getByRole('switch', { name: 'Keep screen on' })
+      fireEvent.click(keepOn)
+      await waitFor(() => expect(wakeLock.request).toHaveBeenCalledTimes(1))
+
+      act(() => letGo(wakeLock.sentinels[0]!))
+      await waitFor(() => expect(wakeLock.request).toHaveBeenCalledTimes(2))
+      await act(async () => {})
+      expect(keepOn).toHaveAttribute('aria-checked', 'true')
+
+      // The fresh lock is watched too.
+      act(() => letGo(wakeLock.sentinels[1]!))
+      await waitFor(() => expect(wakeLock.request).toHaveBeenCalledTimes(3))
+      expect(wakeLock.sentinels[2]!.released).toBe(false)
+      expect(keepOn).toHaveAttribute('aria-checked', 'true')
+    })
+
+    it('asks for the lock again when the page was hidden and shown while a request was pending', async () => {
+      const wakeLock = stubWakeLock({ hold: true })
+      serve()
+      await renderPage()
+      const keepOn = screen.getByRole('switch', { name: 'Keep screen on' })
+      fireEvent.click(keepOn)
+      expect(wakeLock.request).toHaveBeenCalledTimes(1)
+
+      // Hidden and shown again before the first lock is granted, which the
+      // browser has let go by the time it is.
+      act(() => setVisibility('hidden'))
+      act(() => setVisibility('visible'))
+      expect(wakeLock.request).toHaveBeenCalledTimes(1)
+      letGo(wakeLock.sentinels[0]!)
+      await act(async () => wakeLock.grant())
+      expect(wakeLock.request).toHaveBeenCalledTimes(2)
+
+      await act(async () => wakeLock.grant())
+      expect(wakeLock.sentinels[1]!.released).toBe(false)
+      expect(wakeLock.request).toHaveBeenCalledTimes(2)
+      expect(keepOn).toHaveAttribute('aria-checked', 'true')
+    })
+
+    it('reports a lock the browser refuses and turns the switch back off', async () => {
+      const wakeLock = stubWakeLock()
+      wakeLock.request.mockRejectedValueOnce(new DOMException('Blocked by permissions policy', 'NotAllowedError'))
+      serve()
+      await renderPage()
+      const keepOn = screen.getByRole('switch', { name: 'Keep screen on' })
+      fireEvent.click(keepOn)
+
+      expect(await screen.findByRole('alert')).toHaveTextContent(
+        "Couldn't keep the screen on: NotAllowedError: Blocked by permissions policy",
+      )
+      expect(keepOn).toHaveAttribute('aria-checked', 'false')
+
+      fireEvent.click(screen.getByRole('button', { name: 'Retry' }))
+      expect(keepOn).toHaveAttribute('aria-checked', 'true')
+      await waitFor(() => expect(wakeLock.request).toHaveBeenCalledTimes(2))
+      expect(screen.queryByRole('alert')).not.toBeInTheDocument()
+    })
+
+    it('is disabled, and says why, in a browser that cannot keep the screen on', async () => {
+      serve()
+      await renderPage()
+      const keepOn = screen.getByRole('switch', { name: 'Keep screen on' })
+      expect(keepOn).toBeDisabled()
+      expect(keepOn).toHaveAttribute('aria-checked', 'false')
+      expect(keepOn).toHaveAccessibleDescription(
+        "This browser can't keep the screen on, so it may dim while you cook.",
+      )
+      fireEvent.click(keepOn)
+      expect(keepOn).toHaveAttribute('aria-checked', 'false')
+    })
+  })
+})