testWithSpectron.js

const {execa} = require('execa')
const electronPath = require('electron')
const merge = require('lodash.merge')
const portfinder = require('portfinder')

portfinder.basePort = 9515

module.exports = (spectron, options = {}) =>
  // eslint-disable-next-line no-async-promise-executor
  new Promise(async (resolve, reject) => {
    let log = ''
    let outputDir = ''
    // Launch electron:serve in headless mode
    const child = execa(
      require.resolve('@vue/cli-service/bin/vue-cli-service'),
      ['electron:serve', '--headless', '--mode', options.mode || 'test'],
      {
        env: {
          ...process.env,
          NODE_ENV: !options.forceDev ? 'production' : 'development'
        }
      }
    )
    // Exit if electron:serve throws an error
    child.on('error', (err) => {
      reject(err)
    })
    child.stdout.on('data', async (data) => {
      data = data.toString()
      log += data
      const urlMatch = data.match(/\$WEBPACK_DEV_SERVER_URL=https?:\/\/[^/]+\/?/)
      const outputDirMatch = data.match(/\$outputDir=\b.*\b/)
      if (outputDirMatch) {
        // Record output dir
        outputDir = outputDirMatch[0].split('=')[1]
      }
      if (urlMatch) {
        // Record url and launch spectron
        const url = urlMatch[0].split('=')[1]
        let app
        if (!options.noSpectron) {
          const spectronOptions = merge(
            {
              path: electronPath,
              args: [`${outputDir}`],
              env: {
                IS_TEST: true
              },
              // Make sure tests do not interfere with each other
              port: await portfinder.getPortPromise()
            },
            // Apply user options
            options.spectronOptions
          )
          // Launch app with spectron
          app = new spectron.Application(spectronOptions)
          if (!options.noStart) {
            await app.start()
            await app.client.waitUntilWindowLoaded()
          }
        }
        resolve({
          stdout: log,
          url,
          app,
          stopServe: () => {
            // Exit serve process
            child.stdin.write('close')
            child.kill('SIGKILL')
            // Close spectron
            if (app && app.isRunning()) return app.stop()
          }
        })
      }
    })
  })