Forumouth/gulp-karma-runner

((req) => {
  const Base = req('./base.js');
  const cp = req('child_process');
  const PluginError = req('plugin-error');
  const karma = req('karma');
  class ServerPlugin extends Base {
    spawnProcess(cb) {
      const stderr = [];
      const server = cp.spawn('node', [req.resolve('../bin/server.js')], {
        stdio: ['pipe', 'ignore', 'pipe', 'ipc'],
      });
      server.on('message', (msg) => {
        this.emit(`karma.server.${msg}`);
      });
      server.stderr.on('data', (data) => stderr.push(data));
      server.on('error', (err) => {
        this.emit(
          'error', new PluginError(
            'karma.server', err.message, { error: err }
          )
        );
      });
      server.on('exit', (code, signal) => {
        if (code || (signal && signal.length) || stderr.length) {
          this.emit(
            'error', new PluginError(
              'karma.server',
              `The server exited with code: ${code} signal: ${signal}
               stderr: ${stderr.join('')}`,
              { code, signal, stderr: stderr.join('') }
            )
          );
          return;
        }
        cb();
      });
      process.on('exit', () => server.kill());
      server.stdin.end(JSON.stringify(this.conf));
    }

    karmaMode(cb) {
      const svr = new karma.Server(this.conf, (code) => {
        if (code) {
          this.emit('error', new PluginError(
            'karma.server', `The server exited with code: ${code}`, { code }
          ));
          return;
        }
        cb();
      });
      svr.on('browsers_ready', () => this.emit('karma.server.browsers_ready'));
      svr.start();
    }

    _flush(cb) {
      if (this.quiet) this.spawnProcess(cb);
      else this.karmaMode(cb);
    }
  }
  module.exports = (config) => new ServerPlugin(config);
})(require);