Question

这是函数，它使用Operation（NSOperation）：

    typealias ResultType = Result<Data>
    typealias CompletionType = (ResultType) -> ()
    public var onCompletion: CompletionType?

  internal func getNetworkConnection(urlRequest: URLRequest, completionHandler: @escaping CompletionType)  {

        let task = self.urlSession.dataTask(with: urlRequest, completionHandler: { [weak self] (data, response, error) in
            guard let strongSelf = self else {
                return
            }

            if let errorResponse = error {
                //strongSelf.result = Result.failure(errorResponse)

                     strongSelf.onCompletion?(Result.failure(errorResponse))

            }

             if let responseFromServer = response as? HTTPURLResponse,
                200...299 ~= responseFromServer.statusCode{

                if let dataResponse = data{
                    //strongSelf.result = Result.success(dataResponse)


                    strongSelf.onCompletion?(Result.success(dataResponse))//it hits this point 


                } else {
                    strongSelf.onCompletion?(Result.failure(NSError()))
                }
             }

            strongSelf.urlSession.invalidateAndCancel()
        })

        task.resume()
    }

我正在为它编写一个单元测试但是它似乎没有在完成块中，即使它击中了：strongSelf.onCompletion?(Result.success(dataResponse))

到目前为止，这是单元测试的样子：

func test_getNetworkConnection(){

    let promise = expectation(description: "Completion handler invoked")

  sut?.getNetworkConnection(urlRequest: URLRequest(url: requestURL), completionHandler: { (data) in

        print(data) //never prints

        promise.fulfill()
    })

    wait(for: [promise], timeout: 100, enforceOrder: true)//exaggerated timeout but it fails
  //  XCTAssertTrue(returnedResponse!)
}

知道可能是什么问题吗？

Answer 1

你有一些问题。

在数据任务的完成块内，您正在调用strongSelf.onCompletion?...，但onCompletion为nil，因此它无法执行任何操作。
您的getNetworkConnection函数有一个永不使用的completionHandler参数。
您对getNetworkConnection的来电取决于被调用的completionHandler。

onCompletion属性似乎没有意义。

在数据任务中，通过调用strongSelf.onCompletion?...参数替换对completionHandler的调用。

typealias ResultType = Result<Data>
typealias CompletionType = (ResultType) -> ()

internal func getNetworkConnection(urlRequest: URLRequest, completionHandler: @escaping CompletionType)  {
    let task = self.urlSession.dataTask(with: urlRequest, completionHandler: { [weak self] (data, response, error) in
        guard let strongSelf = self else {
            return
        }

        if let errorResponse = error {
            completionHandler(Result.failure(errorResponse))
        }

        if let responseFromServer = response as? HTTPURLResponse,
            200...299 ~= responseFromServer.statusCode{

            if let dataResponse = data{
                completionHandler(Result.success(dataResponse))
            } else {
                completionHandler(Result.failure(NSError()))
            }
        } else {
            // TODO - need to call completionHandler here too
        }

        strongSelf.urlSession.invalidateAndCancel()
    })

    task.resume()
}

完成处理程序没有返回任何东西，即使它看起来像是踩到它时

1 个答案: