next.js/test/lib/development-sandbox.ts

import {
  hasErrorToast,
  getRedboxComponentStack,
  getRedboxDescription,
  getRedboxHeader,
  getRedboxSource,
  getVersionCheckerText,
  hasRedbox,
  waitFor,
  waitForAndOpenRuntimeError,
  getRedboxDescriptionWarning,
  toggleCollapseComponentStack,
} from './next-test-utils'
import webdriver from './next-webdriver'
import { NextInstance } from './next-modes/base'
import { BrowserInterface } from './browsers/base'

export function waitForHydration(browser: BrowserInterface): Promise<void> {
  return browser.evalAsync(function () {
    var callback = arguments[arguments.length - 1]
    if ((window as any).__NEXT_HYDRATED) {
      callback()
    } else {
      var timeout = setTimeout(callback, 30 * 1000)
      ;(window as any).__NEXT_HYDRATED_CB = function () {
        clearTimeout(timeout)
        callback()
      }
    }
  })
}

export async function sandbox(
  next: NextInstance,
  initialFiles?: Map<string, string>,
  initialUrl: string = '/',
  webDriverOptions: any = undefined
) {
  await next.stop()
  await next.clean()

  if (initialFiles) {
    for (const [k, v] of initialFiles.entries()) {
      await next.patchFile(k, v)
    }
  }

  await next.start()
  const browser = await webdriver(next.url, initialUrl, webDriverOptions)
  return {
    browser,
    session: {
      async write(filename, content) {
        // Update the file on filesystem
        await next.patchFile(filename, content)
      },
      async patch(filename, content) {
        // Register an event for HMR completion
        await browser.eval(function () {
          ;(window as any).__HMR_STATE = 'pending'

          var timeout = setTimeout(() => {
            ;(window as any).__HMR_STATE = 'timeout'
          }, 30 * 1000)
          ;(window as any).__NEXT_HMR_CB = function () {
            clearTimeout(timeout)
            ;(window as any).__HMR_STATE = 'success'
          }
        })

        await this.write(filename, content)

        for (;;) {
          const status = await browser.eval(() => (window as any).__HMR_STATE)
          if (!status) {
            await waitFor(750)

            // Wait for application to re-hydrate:
            await waitForHydration(browser)

            console.log('Application re-loaded.')
            // Slow down tests a bit:
            await waitFor(750)
            return false
          }
          if (status === 'success') {
            console.log('Hot update complete.')
            break
          }
          if (status !== 'pending') {
            throw new Error(`Application is in inconsistent state: ${status}.`)
          }

          await waitFor(30)
        }

        // Slow down tests a bit (we don't know how long re-rendering takes):
        await waitFor(750)
        return true
      },
      async remove(filename) {
        await next.deleteFile(filename)
      },
      async evaluate(snippet: string | Function) {
        if (typeof snippet === 'function' || typeof snippet === 'string') {
          const result = await browser.eval(snippet)
          await waitFor(30)
          return result
        } else {
          throw new Error(
            `You must pass a string or function to be evaluated in the browser.`
          )
        }
      },
      async hasRedbox() {
        return hasRedbox(browser)
      },
      async waitForAndOpenRuntimeError() {
        return waitForAndOpenRuntimeError(browser)
      },
      async hasErrorToast() {
        return Boolean(await hasErrorToast(browser))
      },
      async getRedboxDescription() {
        return getRedboxDescription(browser)
      },
      async getRedboxDescriptionWarning() {
        return getRedboxDescriptionWarning(browser)
      },
      async getRedboxSource(includeHeader = false) {
        const header = includeHeader ? await getRedboxHeader(browser) : ''
        const source = await getRedboxSource(browser)

        if (includeHeader) {
          return `${header}\n\n${source}`
        }
        return source
      },
      async getRedboxComponentStack() {
        return getRedboxComponentStack(browser)
      },
      async toggleCollapseComponentStack() {
        return toggleCollapseComponentStack(browser)
      },
      async getVersionCheckerText() {
        return getVersionCheckerText(browser)
      },
    },
    async cleanup() {
      await browser.close()
      await next.stop()
      await next.clean()
    },
  }
}