next.js/test/e2e/app-dir/app-rendering/rendering.test.ts

import { nextTestSetup } from 'e2e-utils'
import { waitFor } from 'next-test-utils'
import cheerio from 'cheerio'

describe('app dir rendering', () => {
  const { next, isNextDev, skipped } = nextTestSetup({
    files: __dirname,
    skipDeployment: true,
  })

  if (skipped) {
    return
  }

  it('should serve app/page.server.js at /', async () => {
    const html = await next.render('/')
    expect(html).toContain('app/page.server.js')
  })

  describe('SSR only', () => {
    it('should run data in layout and page', async () => {
      const $ = await next.render$('/ssr-only/nested')
      expect($('#layout-message').text()).toBe('hello from layout')
      expect($('#page-message').text()).toBe('hello from page')
    })

    it('should run data fetch in parallel', async () => {
      const startTime = Date.now()
      const $ = await next.render$('/ssr-only/slow')
      const endTime = Date.now()
      const duration = endTime - startTime
      // Each part takes 5 seconds so it should be below 10 seconds
      // Using 7 seconds to ensure external factors causing slight slowness don't fail the tests
      expect(duration).toBeLessThan(10_000)
      expect($('#slow-layout-message').text()).toBe('hello from slow layout')
      expect($('#slow-page-message').text()).toBe('hello from slow page')
    })
  })

  describe('static only', () => {
    it('should run data in layout and page', async () => {
      const $ = await next.render$('/static-only/nested')
      expect($('#layout-message').text()).toBe('hello from layout')
      expect($('#page-message').text()).toBe('hello from page')
    })

    it(`should run data in parallel ${
      isNextDev ? 'during development' : 'and use cached version for production'
    }`, async () => {
      // const startTime = Date.now()
      const $ = await next.render$('/static-only/slow')
      // const endTime = Date.now()
      // const duration = endTime - startTime
      // Each part takes 5 seconds so it should be below 10 seconds
      // Using 7 seconds to ensure external factors causing slight slowness don't fail the tests
      // TODO: cache static props in prod
      // expect(duration < (isDev ? 7000 : 2000)).toBe(true)
      // expect(duration < 7000).toBe(true)
      expect($('#slow-layout-message').text()).toBe('hello from slow layout')
      expect($('#slow-page-message').text()).toBe('hello from slow page')
    })
  })

  describe('ISR', () => {
    it('should revalidate the page when revalidate is configured', async () => {
      const getPage = async () => {
        const res = await next.fetch('isr-multiple/nested')
        const html = await res.text()

        return {
          $: cheerio.load(html),
          cacheHeader: res.headers['x-nextjs-cache'],
        }
      }
      const { $ } = await getPage()
      expect($('#layout-message').text()).toBe('hello from layout')
      expect($('#page-message').text()).toBe('hello from page')

      const layoutNow = $('#layout-now').text()
      const pageNow = $('#page-now').text()

      await waitFor(2000)

      // TODO: implement
      // Trigger revalidate
      // const { cacheHeader: revalidateCacheHeader } = await getPage()
      // expect(revalidateCacheHeader).toBe('STALE')

      // TODO: implement
      const { $: $revalidated /* cacheHeader: revalidatedCacheHeader */ } =
        await getPage()
      // expect(revalidatedCacheHeader).toBe('REVALIDATED')

      const layoutNowRevalidated = $revalidated('#layout-now').text()
      const pageNowRevalidated = $revalidated('#page-now').text()

      // Expect that the `Date.now()` is different as the page have been regenerated
      expect(layoutNow).not.toBe(layoutNowRevalidated)
      expect(pageNow).not.toBe(pageNowRevalidated)
    })
  })

  // TODO: implement
  describe.skip('mixed static and dynamic', () => {
    it('should generate static data during build and use it', async () => {
      const getPage = async () => {
        const $ = await next.render$('isr-ssr-combined/nested')

        return {
          $,
        }
      }
      const { $ } = await getPage()
      expect($('#layout-message').text()).toBe('hello from layout')
      expect($('#page-message').text()).toBe('hello from page')

      const layoutNow = $('#layout-now').text()
      const pageNow = $('#page-now').text()

      const { $: $second } = await getPage()

      const layoutNowSecond = $second('#layout-now').text()
      const pageNowSecond = $second('#page-now').text()

      // Expect that the `Date.now()` is different as it came from getServerSideProps
      expect(layoutNow).not.toBe(layoutNowSecond)
      // Expect that the `Date.now()` is the same as it came from getStaticProps
      expect(pageNow).toBe(pageNowSecond)
    })
  })
})