title: How to test a sendAsynchronousRequest: on XCTest
body: <p>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:</p>
  
  <pre><code>-(void)testConnection
  {
  
      [[Conector sharedInstance] performAsynchronousRequestWithServerRequest:_srvRequest completionHandler:^(RequestAsynchronousStatus finishStatus, NSData *data) {
          if (finishStatus == RequestAsynchronousOK){
              _data = data;
              NSLog(@"Data OK");
          }
      }];
  
      XCTAssertNotNil(_data, @"Data was nil");
  
  }
  </code></pre>
  
  <p>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.</p>