How to test a sendAsynchronousRequest: on XCTest

Question

Sorry for the noob question, but I'm trying to test a connection, but I'm not able do verify the return of the request, because the test ends before the completion handler have a chance to execute. To ilustrate:

-(void)testConnection
{

    [[Conector sharedInstance] performAsynchronousRequestWithServerRequest:_srvRequest completionHandler:^(RequestAsynchronousStatus finishStatus, NSData *data) {
        if (finishStatus == RequestAsynchronousOK){
            _data = data;
            NSLog(@"Data OK");
        }
    }];

    XCTAssertNotNil(_data, @"Data was nil");

}

When I try to assert, _data will always be nil, because the completion handler wasn't executed yet. There is a mechanism to force the test to wait until I have some response from the sendAsynchronousRequest: method. Thanks in advance.

Answer 1

This looks like exactly what you need:

XCAsyncTestCase: Asynchronous capable SenTestCase subclass.

Basically, you should write your test like this:

- (void)testConnection
{
    [[Conector sharedInstance] performAsynchronousRequestWithServerRequest:_srvRequest completionHandler:^(RequestAsynchronousStatus finishStatus, NSData *data) {
        if (finishStatus == RequestAsynchronousOK)
        {
            _data = data;
            [self notify:XCTAsyncTestCaseStatusSucceeded];
            NSLog(@"Data OK");
        }
    }];

    [self waitForTimeout:10];

    XCTAssertNotNil(_data, @"Data was nil");
}

Notice the waitForTimeout: call and the notify: calls. 10 seconds should be enough for the test, though it would depend on the request itself.

You could even get more specific and wait for a certain status, like so:

[self waitForStatus: XCTAsyncTestCaseStatusSucceeded timeout:10];

This way, if the connection fails to notify the XCTAsyncTestCaseStatusSucceeded status, the wait call will timeout and your test would fail (as it should).