Method if

testing/test-config.js:111–114

* @param {function():boolean} fn

(fn)

   * @param {function():boolean} fn
   */
  if(fn) {
    this.ifMatchers.push(fn);
    return this;
  }

  isSkipped() {
    for (let i = 0; i < this.skipMatchers.length; i++) {