code: function(code){
          this.obj.should.have.property('statusCode');
          var status = this.obj.statusCode;
  
          this.assert(
              code == status
              , function(){ return 'expected response code of ' + code + ' ' + i(statusCodes[code])
                  + ', but got ' + status + ' ' + i(statusCodes[status]) }
              , function(){ return 'expected to not respond with ' + code + ' ' + i(statusCodes[code]) });
  
          return this;
      }
docs: Assert `.statusCode` of `code`.
  
  @param {Number} code
  @return {Assertion} for chaining
  @api public