/**
  * @private
  */
 _failExpected(relation, expected) {
     let act = describe(this.subject);
     let exp = describe(expected);
     if (act.length + exp.length < 50) {
         this._fail(`Got <${act}> but expected it ${relation} <${exp}>.`);
     } else {
         this._fail(`Got <\n\t${act}\n> but expected it ${relation} <\n\t${exp}\n>.`);
     }
 }
 /**
  * @param {!string} message
  * @private
  */
 _fail(message) {
     let idMessage = this.id === undefined ? message : `${message} (${this.id})`;
     let infoMessage = this.info === undefined ? idMessage : `${idMessage} (info: ${describe(this.info)})`;
     fail(infoMessage);
 }