headless.js

const handler = require('serve-handler')
const { createServer } = require('http')
const launcher = require('chrome-launcher')
const remoteInterface = require('chrome-remote-interface')

let exitStatus = 0

const baseURL = 'http://localhost:6000'

const server = createServer((request, response) => {
  return handler(request, response)
})

server.listen(6000, async () => {
  console.log(`Running at ${baseURL}`)

  const chrome = await launcher.launch({
    startingUrl: `${baseURL}/blank`,
    chromeFlags: ['--headless', '--disable-gpu', '--no-sandbox', '--explicitly-allowed-ports=6000'],
    logLevel: 'info'
  })

  const tid = setTimeout(() => {
    console.log('timed out')
    chrome.kill().then(() => {
      process.exit(1)
    })
  }, 50000)

  console.log(`Chrome debugging port running on ${chrome.port}`)
  let client

  try {
    client = await remoteInterface({ port: chrome.port })

    const { Page, Runtime } = client

    await Promise.all([
      Runtime.enable(),
      Page.enable()
    ])

    const finishedLogs = new Promise((resolve, reject) => {
      Runtime.consoleAPICalled((entry) => {
        clearTimeout(tid)

        if (entry.args.length === 1 &&
            entry.args[0].type === 'string') {
          const value = entry.args[0].value.trim()

          console.log(value)

          if (value.startsWith('# fail ')) {
            const failed = value.replace(/^# fail /, '')

            if (failed === '0') {
              resolve(true)
            } else {
              reject(new Error(`${failed} tests failed`))
            }
          }
        } else {
          console.debug(entry.toString())
        }
      })
    })

    const loadEvent = new Promise(resolve => {
      Page.loadEventFired(e => resolve(e))
    })

    console.log(`navigate to ${baseURL}/?reporter=tap`)
    await Page.navigate({ url: `${baseURL}/?reporter=tap` })

    await loadEvent

    console.debug('location', (await Runtime.evaluate({ expression: 'window.location.toString()' })).result.value)

    setTimeout(async () => {
      const evaluation = await Runtime.evaluate({ expression: 'window.mocha.run()' })

      if (evaluation.result.subtype === 'error') {
        throw new Error('error running mocha')
      }
    }, 1000)

    await finishedLogs
  } catch (e) {
    console.error(e)
    exitStatus = 1
  } finally {
    console.debug('Shutting down....')
    if (client) {
      await client.close()
    }
    await chrome.kill()
    process.exit(exitStatus)
  }
})