rsnext/test/lib/e2e-utils.ts

import path from 'path'
import assert from 'assert'
import { NextConfig } from 'next'
import { NextInstance } from './next-modes/base'
import { NextDevInstance } from './next-modes/next-dev'
import { NextStartInstance } from './next-modes/next-start'

const testFile = module.parent.filename
const testsFolder = path.join(__dirname, '..')

let testMode = process.env.NEXT_TEST_MODE

if (!testFile.match(/\.test\.(js|tsx?)/)) {
  throw new Error(
    'e2e-utils imported from non-test file (must end with .test.(js,ts,tsx)'
  )
}

const testFolderModes = ['e2e', 'development', 'production']

const testModeFromFile = testFolderModes.find((mode) =>
  testFile.startsWith(path.join(testsFolder, mode))
)

if (testModeFromFile === 'e2e') {
  const validE2EModes = ['dev', 'start', 'deploy']

  if (!process.env.NEXT_TEST_JOB && !testMode) {
    console.warn('Warn: no NEXT_TEST_MODE set, using default of start')
    testMode = 'start'
  }
  assert(
    validE2EModes.includes(testMode),
    `NEXT_TEST_MODE must be one of ${validE2EModes.join(
      ', '
    )} for e2e tests but received ${testMode}`
  )
} else if (testModeFromFile === 'development') {
  testMode = 'dev'
} else if (testModeFromFile === 'production') {
  testMode = 'start'
}

if (testMode === 'dev') {
  ;(global as any).isDev = true
} else if (testMode === 'deploy') {
  ;(global as any).isDeploy = true
}

if (!testMode) {
  throw new Error(
    `No 'NEXT_TEST_MODE' set in environment, this is required for e2e-utils`
  )
}
console.log(`Using test mode: ${testMode} in test folder ${testModeFromFile}`)

/**
 * FileRef is wrapper around a file path that is meant be copied
 * to the location where the next instance is being created
 */
export class FileRef {
  public fsPath: string

  constructor(path: string) {
    this.fsPath = path
  }
}

let nextInstance: NextInstance | undefined = undefined

if (typeof afterAll === 'function') {
  afterAll(async () => {
    if (nextInstance) {
      await nextInstance.destroy()
      throw new Error(
        `next instance not destroyed before exiting, make sure to call .destroy() after the tests after finished`
      )
    }
  })
}

/**
 * Sets up and manages a Next.js instance in the configured
 * test mode. The next instance will be isolated from the monorepo
 * to prevent relying on modules that shouldn't be
 */
export async function createNext(opts: {
  files: {
    [filename: string]: string | FileRef
  }
  dependencies?: {
    [name: string]: string
  }
  nextConfig?: NextConfig
  skipStart?: boolean
}): Promise<NextInstance> {
  if (nextInstance) {
    throw new Error(`createNext called without destroying previous instance`)
  }

  if (testMode === 'dev') {
    // next dev
    nextInstance = new NextDevInstance(opts)
  } else if (testMode === 'deploy') {
    // Vercel
    throw new Error('to-implement')
  } else {
    // next build + next start
    nextInstance = new NextStartInstance(opts)
  }

  nextInstance.on('destroy', () => {
    nextInstance = undefined
  })

  await nextInstance.setup()

  if (!opts.skipStart) {
    await nextInstance.start()
  }
  return nextInstance!
}