check = function () {
            var now = that.getTime();

            if (now - start >= timeoutValue) {
              reject(new Error('' + timeoutValue + 'ms timeout exceeded'));
            } else {
              that['context'].document.fonts.load(that.getStyle('"' + that['family'] + '"'), testString).then(function (fonts) {
                if (fonts.length >= 1) {
                  resolve();
                } else {
                  setTimeout(check, 25);
                }
              }, reject);
            }
          }
@param {string=} text Optional test string to use for detecting if a font is available.
@param {number=} timeout Optional timeout for giving up on font load detection and rejecting the promise (defaults to 3 seconds).
@return {Promise.<fontface.Observer>}