title: failing a XCTestCase with assert without the test continuing to run but without stopping other tests
body: <p>I'm trying to test my application using the XCTest framework.</p>
  
  <p>I want my single test case to fail if some logical condition holds (using an assertion).
  I don't want the rest of the code in the test case to run, because this might lead to problems (access to null pointers, for example)
  I also want the rest of the test case to run normally, and just the failed test to be marked as failed.</p>
  
  <p>I've noticed XCTestCase has a property called continueAfterFailure. 
  However, setting it to YES caused the failed test to continue executing lines after the assertion, and setting it to NO caused the rest of the tests not to run at all.</p>
  
  <p>Is there a solution to this issue?</p>