                 XCTFail("previous result shoule be String.")
             }
             return nil
-        }
-        
-        task.waitUntilCompleted()
+        }.waitUntilCompleted()
     }
     
     func testRejectShouldCauseError() {

                XCTFail("previous result shoule be Int.")
            }
            return nil
        }
        
        task.waitUntilCompleted()
    }
    
    func testReturnValueShouldBeResult() {

                XCTFail("error value shoule be exist.")
            }
            return nil
        }.waitUntilCompleted()
    }
}
