title: Xcode 5 xcodebuild unit test seems to return status successful when tests fail
body: <p>Hi I'm following examples from Test Driven iOS development and I've written a few unit tests with the new Xcode 5 and XCTest. My tests fail with the Xcode GUI client, but when I use xcodebuild the status code is 0.</p>
  
  <p><code>xcodebuild -target TemperatureConverterTests build</code></p>
  
  <p>and </p>
  
  <p><code>echo $?</code></p>
  
  <p>returns 0.</p>
  
  <p>The tests are suppose to fail. Is the command to run the test cases correct?</p>