title: OCMock Failing at runtime
body: <p>I'm trying to use OCMock for the first time in my test cases. It's a Mac project, built on and targeting Lion, in Xcode 4.3. The main app and the test bundle both have ARC turned on, and so every time I execute the tests I see the following log message:</p>
  
  <p><code>
  GC: forcing GC OFF because OBJC_DISABLE_GC is set
  </code></p>
  
  <p>That's fine, as I'm using ARC so I don't care about GC. When I build my unit tests, linked against the latest stable release of OCMock (2.0.1), the build has no issues. At runtime, after the above log statement, I get the following:</p>
  
  <p><code>
  The test bundle at /Users/___/Library/Developer/Xcode/DerivedData/___-ayizwpehemunvodsdvczckkvarsh/Build/Products/Debug/___Tests.octest could not be loaded because its Objective-C runtime information does not match the runtime information required by the test rig.  This is likely because the test rig is being run with Objective-C garbage collection disabled, but the test bundle requires Objective-C garbage collection.  To enable Objective-C garbage collection for the test rig, run it in an environment without the OBJC_DISABLE_GC environment variable.
  2012-03-06 10:29:32.812 otest[8486:203] *** NSTask: Task create for path '/Users/___/Library/Developer/Xcode/DerivedData/___-ayizwpehemunvodsdvczckkvarsh/Build/Products/Debug/___Tests.octest/Contents/MacOS/___Tests' failed: 22, "Invalid argument".  Terminating temporary process.
  </code></p>
  
  <p>The message implies that garbage collection is the most common culprit, but as mentioned, there is no way I'm using GC. So, what other settings could be messing me up at runtime? I didn't think I'm doing anything atypical, and I've looked through my test project's settings to be sure, and didn't see anything weird.</p>
  
  <p><strong>Update</strong></p>
  
  <p>I was able to reproduce this with a new empty project.</p>
  
  <ol>
  <li>Create a new project and have it create unit tests, with ARC enabled</li>
  <li>Clear the <code>Test Host</code> setting from the unit test bundle's build settings</li>
  <li>Link to the OCMock framework</li>
  <li>Execute the tests, and witness the same error I reported above</li>
  </ol>
  
  <p>Also, when I turn off ARC and make garbage collection <strong>Required</strong>, then <code>clang</code> reports a mach-o linker error, so the build doesn't succeed. If I remove the link to the OCMock framework, it builds fine. This supports my initial thought that the problem lies somewhere other than garbage collection.</p>