Sample iOS Unit Tests: Model can Process the Response From Async Network Request

Sample iOS Unit Tests: Model can Process the Response From Async Network Request

- (void)testFetchingFoursquareVenues {

    //create a semaphore with initial value
    dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

    NSURL *url = [NSURL URLWithString:@"https://api.yourawesome.com"];

    NSURLSessionDataTask *task = [self.session dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {

        XCTAssertNil(error, @"NSURLSessionDataTask returned completed with Error: %@", error);

        NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;

        NSInteger statusCode = [httpResponse statusCode];

        XCTAssertEqual(statusCode, 200, @"NSURLSessionDataTask did not complete with status code 200. Check the request URL.  Returned Status Code of: %ld", (long)statusCode);

        if(statusCode == 200) {

            XCTAssertNotNil(data, @"NSURLSessionDataTask did not return data");

            NSDictionary *responseDict = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];

            NSArray *collectionOfStuff = [MyFetcher serializeTheStuffForResponse:responseDict];

            XCTAssertTrue(collectionOfStuff.count > 0, @"Failed to serialize to a collection of stuff");

            MyStuff *stuff = [collectionOfStuff lastObject];

            XCTAssertTrue([venue isKindOfClass:[MyStuff class]], @"Collection does not have objects of type MyStuff");

            //increment the semaphore
            dispatch_semaphore_signal(semaphore);
        }
    }];

    [task resume];

    //decrement the semaphore
    long rc = dispatch_semaphore_wait(semaphore, dispatch_time(DISPATCH_TIME_NOW, 2.0 * NSEC_PER_SEC));

    XCTAssertEqual(rc, 0, @"Network request timed out.");
}