XCTest and asynchronous testing in Xcode 6

Question

So Apple said in the release note of Xcode 6 that we can now do asynchronous testing directly with XCTest.

Anyone knows how to do it using Xcode 6 Beta 3 (Using objective-C or Swift)? I don't want the known semaphore method, but the new Apple way.

I searched into the released note and more but I found nothing. The XCTest header is not very explicit either.

score 68 · Answer 1 · answered Sep 19 '14 at 01:57

Obj-C example:

- (void)testAsyncMethod
{

    //Expectation
    XCTestExpectation *expectation = [self expectationWithDescription:@"Testing Async Method Works!"];

    [MyClass asyncMethodWithCompletionBlock:^(NSError *error, NSHTTPURLResponse *httpResponse, NSData *data) {

        if(error)
        {
            NSLog(@"error is: %@", error);
        }else{
            NSInteger statusCode = [httpResponse statusCode];
            XCTAssertEqual(statusCode, 200);
            [expectation fulfill];
        }

    }];


    [self waitForExpectationsWithTimeout:5.0 handler:^(NSError *error) {

        if(error)
        {
            XCTFail(@"Expectation Failed with error: %@", error);
        }

    }];
}

silly question: what if my `asyncMethod` doesn´t have a completion block? I have no idea how to test this. — 最白目, Nov 17 '15 at 14:47
Assuming you run it on a dispatch_queue, you can schedule your test on the same queue after you started the work you were planning on doing. Just dispatch_async onto the same queue and then in that continuation block do what you need to — Bob9630, Mar 08 '16 at 20:33

score 52 · Accepted Answer · edited Aug 25 '16 at 19:42

52

The sessions video is perfect, basically you want to do something like this

func testFetchNews() {
    let expectation = self.expectationWithDescription("fetch posts")

    Post.fetch(.Top, completion: {(posts: [Post]!, error: Fetcher.ResponseError!) in
        XCTAssert(true, "Pass")
        expectation.fulfill()
    })

    self.waitForExpectationsWithTimeout(5.0, handler: nil)
}

edited Aug 25 '16 at 19:42

onmyway133

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answered Jul 11 '14 at 19:38

Dimillian

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score 11 · Answer 3 · answered Jul 11 '14 at 19:06

11

Session 414 covers async testing in Xcode6

https://developer.apple.com/videos/wwdc/2014/#414

answered Jul 11 '14 at 19:06

mittens

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To make it easier to find in the list: this session is named "Testing in Xcode 6". – Ashley Sep 12 '14 at 12:48

score 1 · Answer 4 · answered Mar 02 '16 at 10:45

How I did in swift2

Step 1: define expectation

let expectation = self.expectationWithDescription("get result bla bla")

Step 2: tell the test to fulfill expectation right below where you capture response

responseThatIGotFromAsyncRequest = response.result.value
expectation.fulfill()

Step 3: Tell the test to wait till the expectation is fulfilled

waitForExpectationsWithTimeout(10)

STep 4: make assertion after async call is finished

XCTAssertEqual(responseThatIGotFromAsyncRequest, expectedResponse)

XCTest and asynchronous testing in Xcode 6

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