code: function bindServe() {
    return new Promise((resolve, reject) => {
  
      // Logging "warnings" but not rejecting test
      webpackServer.stderr.on('data', data => log(data));
      webpackServer.stdout.on('data', data => {
        const dataAsString = log(data);
        if (dataAsString.indexOf('webpack: Compiled successfully.') > -1) {
          resolve(_port);
        }
        if (dataAsString.indexOf('webpack: Failed to compile.') > -1) {
          reject(dataAsString);
        }
      });
    });
  }
docs: Adds event listeners to serve and resolves a promise.