code: function (name, f) {
      if (!f) throw new Error('Undefined test function');
      if (!/function[^\(]*\(([^,\)]*)/.test(f.toString())) {
        throw new Error('"' + name + '" test: Test is not a valid Function object');
      }
      this.loopArg = RegExp.$1;
      this.name = name;
      this.f = f;
    }
docs: Test manages a single test (created with
  JSLitmus.test())
  
  @private