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

        task.reject(MyError(message: "error"))
        task.continueWith { context in
            continued = true
        }
        task.waitUntilCompleted()
        XCTAssertTrue(continued, "continuation closure should run.")
    }
    

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