mocha-chrome/index.js

const deepAssign = require('deep-assign');

const log = require('loglevel');
const unmirror = require('chrome-unmirror');

const createInstance = require('./lib/instance');
const connectClient = require('./lib/client');
const EventBus = require('./lib/event-bus');
const chromeOut = require('./lib/chrome-out');
const network = require('./lib/network');

process.on('unhandledRejection', (error) => {
  const { error: stderr } = console;
  // this should always output to console.error, regardless of loglevel
  stderr('Promise Rejection: ', error);
});

class MochaChrome {
  constructor(options) {
    // eslint-disable-next-line no-param-reassign
    options = deepAssign(
      {
        chromeFlags: [],
        loadTimeout: 1000,
        logLevel: 'error',
        ignoreExceptions: false,
        ignoreConsole: false,
        ignoreResourceErrors: false,
        mocha: {
          reporter: 'spec',
          ui: 'bdd',
          useColors: true
        }
      },
      options
    );

    log.setDefaultLevel('error');
    log.setLevel(options.logLevel);

    const bus = new EventBus(log);

    if (!options.url) {
      this.fail('`options.url` must be specified to run tests');
    }

    bus.on('ready', (/* content */) => {
      this.client.Runtime.evaluate({ expression: `mocha.setup({ reporter: 'spec' })` });
    });

    bus.on('mocha', (content) => {
      process.stdout.write(content);
    });

    bus.on('width', (/* content */) => {
      // eslint-disable-next-line no-bitwise
      const columns = (parseInt(process.env.COLUMNS || process.stdout.columns, 10) * 0.75) | 0;
      const expression = `Mocha.reporters.Base.window.width = ${columns};`;

      this.client.Runtime.evaluate({ expression });
    });

    bus.on('config', (/* content */) => {
      const config = JSON.stringify(options.mocha);
      const expression = `mocha.setup(${config})`;

      this.client.Runtime.evaluate({ expression });
    });

    bus.on('started', (tests) => {
      this.started = true;
      log.info(`Test Run Started - Running ${tests} Tests\n`);

      if (tests === 0) {
        this.fail('mocha.run() was called with no tests');
      }
    });

    bus.on('ended', (stats) => {
      this.ended = true;
      this.exit(stats.failures);
    });

    bus.on('resourceFailed', (/* data */) => {
      this.loadError = true;
    });

    this.bus = bus;
    this.options = options;
    this.loadError = false;
  }

  async connect() {
    const instance = await createInstance(log, this.options);
    const client = await connectClient(instance, log, this.options);
    const { DOMStorage, Network, Runtime } = client;

    if (!client) {
      this.fail('CDP Client could not connect');
      return;
    }

    this.bus.watch(DOMStorage);

    chromeOut(log, this.options, Runtime);
    network(this.bus, log, Network, this.options.ignoreResourceErrors);

    this.client = client;
    this.instance = instance;
  }

  async run() {
    this.client.Page.loadEventFired(() => {
      if (this.closed) {
        return;
      }

      if (this.loadError) {
        this.fail(`Failed to load the page. Check the url: ${this.options.url}`);
        return;
      }

      setTimeout(async () => {
        if (this.closed) {
          return;
        }

        const expression = '(function () { return !!window.mocha; })()';
        const res = await this.client.Runtime.evaluate({ expression });

        if (!unmirror(res.result)) {
          this.fail(
            `mocha was not found in the page within ${this.options.loadTimeout}ms of the page loading.`
          );
        }

        if (!this.started) {
          this.fail(
            `mocha.run() was not called within ${this.options.loadTimeout}ms of the page loading.`
          );
        }
      }, this.options.loadTimeout);
    });

    await this.client.Page.navigate({ url: this.options.url });
  }

  on(name, fn) {
    this.bus.on(name, fn);
  }

  fail(message) {
    log.error('Mocha-Chrome Failed:', message || '');

    if (this.bus) {
      this.bus.emit('failure', message);
    }

    this.exit(1);
  }

  async exit(/* code */) {
    this.closed = true;
    await this.client.close();
    await this.instance.kill();

    this.bus.emit('exit', 1);
  }
}

module.exports = MochaChrome;