prefetching.test.ts

import { createNextDescribe } from 'e2e-utils'
import { waitFor } from 'next-test-utils'

createNextDescribe(
  'app dir prefetching',
  {
    files: __dirname,
    skipDeployment: true,
  },
  ({ next, isNextDev }) => {
    // TODO: re-enable for dev after https://vercel.slack.com/archives/C035J346QQL/p1663822388387959 is resolved (Sep 22nd 2022)
    if (isNextDev) {
      it('should skip next deploy for now', () => {})
      return
    }

    it('should show layout eagerly when prefetched with loading one level down', async () => {
      const browser = await next.browser('/')
      // Ensure the page is prefetched
      await waitFor(1000)

      const before = Date.now()
      await browser
        .elementByCss('#to-dashboard')
        .click()
        .waitForElementByCss('#dashboard-layout')
      const after = Date.now()
      const timeToComplete = after - before

      expect(timeToComplete < 1000).toBe(true)

      expect(await browser.elementByCss('#dashboard-layout').text()).toBe(
        'Dashboard Hello World'
      )

      await browser.waitForElementByCss('#dashboard-page')

      expect(await browser.waitForElementByCss('#dashboard-page').text()).toBe(
        'Welcome to the dashboard'
      )
    })

    it('should not have prefetch error for static path', async () => {
      const browser = await next.browser('/')
      await browser.eval('window.nd.router.prefetch("/dashboard/123")')
      await waitFor(3000)
      await browser.eval('window.nd.router.push("/dashboard/123")')
      expect(next.cliOutput).not.toContain('ReferenceError')
      expect(next.cliOutput).not.toContain('is not defined')
    })
  }
)