OCUnit tests not running / not being found

I'm trying to get to grips with OCTest, but can't seem to get it to actually run my tests (at least, I believe it's not running my tests). I've set up a project as described in the developer documentation, and added a class called UnitTests which contains the following function:

-(v开发者_高级运维oid)testFailures
{
    STFail(@"A message");
}

When I build the test bundle (in Debug or Release), the Build Results panel shows briefly that it's running the unit tests (it says something like 'Running unit tests for ... (GC OFF)'), but then shows the Build Succeeded message. The same occurs when I put less trivial tests in, such as:

- (void)testFramework
{
    NSString *string1 = @"test";
    NSString *string2 = @"testing";
    STAssertEquals(string1,
               string2,
               @"FAILURE");
}

Any ideas as to where I'm going wrong?

1. Setting the target for the project to ocunit?
2. In the info for your m file, is it targeting OCUnit?

Here is an Updated Link to the Apple Docs on unit testing.