在 XCTests 中使用 AFHTTPRequestOperation

Question

我有以下测试用例代码：

- (void)testExample {
    // URL https://api.spotify.com/v1/search?q=album%3AJustified%20artist%3AJustin%20Timberlake&type=album


    dispatch_semaphore_t sem = dispatch_semaphore_create(0);
    [[AFHTTPRequestOperationManager manager] GET:@"https://api.spotify.com/v1/search"
                                      parameters:@{@"q":@"album:Justified artist:Justin Timberlake",
                                                   @"type":@"album"}
                                         success:^(AFHTTPRequestOperation *operation, id responseObject) {
                                             dispatch_semaphore_signal(sem);
                                         } failure:^(AFHTTPRequestOperation *operation, NSError *error) {

                                         }
     ];
    dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER);

    // This is an example of a functional test case.
    XCTAssert(YES, @"Pass");
}

我原以为测试用例会阻塞并等待 http 请求完成。奇怪的是 AFHTTPRequestOperation 永远不会到达成功块，即使 url 是有效块。如果我在 XCTest 之外使用以下代码，则不会发生，将执行成功块。有人以前看过这个吗？

Answer 1

一些观察：

您的测试正在冻结，因为 AFNetworking 将其完成块分派到主队列。但是您已经用 dispatch_semaphore_wait 阻塞了主线程，导致了死锁。

您可以通过将管理器的completionQueue设置为全局队列来解决这个问题，以进行测试，从而消除主线程上信号量引起的死锁：

- (void)testExample {
    dispatch_semaphore_t sem = dispatch_semaphore_create(0);

    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];

    manager.completionQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    [manager GET:@"https://api.spotify.com/v1/search" parameters:@{@"q":@"album:Justified artist:Justin Timberlake", @"type":@"album"} success:^(AFHTTPRequestOperation *operation, id responseObject) {
        XCTAssert(YES, @"Pass"); // you might want more rigorous test of results here

        dispatch_semaphore_signal(sem);
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        XCTFail(@"%@", error.localizedDescription);

        dispatch_semaphore_signal(sem);
    }];

    dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER);
}

注意，现在人们会使用 XCTestExpectation 来执行异步测试。这消除了对信号量的需要，巧合的是，也解决了死锁问题：

- (void)testExample {
    XCTestExpectation *expectation = [self expectationWithDescription:@"asynchronous request"];

    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];

    [manager GET:@"https://api.spotify.com/v1/search" parameters:@{@"q":@"album:Justified artist:Justin Timberlake", @"type":@"album"} success:^(AFHTTPRequestOperation *operation, id responseObject) {
        XCTAssert(YES, @"Pass"); // you might want more rigorous test of results here

        [expectation fulfill];
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        XCTFail(@"%@", error.localizedDescription);

        [expectation fulfill];
    }];

    [self waitForExpectationsWithTimeout:30.0 handler:nil];
}

顺便说一下，无论你使用XCTestExpectation还是semaphore，都要确保成功块和失败块都满足expectation/semaphore.

在 XCTests 中使用 AFHTTPRequestOperation

Using AFHTTPRequestOperation in XCTests

objective-c

ios8

afnetworking

xctest