Are there any directives to ignore code during indexing?

My situation is simple:

I am unit testing a php class calles \space1\A. Class A has a member class called \space2\B. I wish to stub class \space2\B and so my unit test file for class \space1\A looks like this:

My situation is simple:  I am unit testing a class calles \space1\A. Class A has a member class called \space2\B. I wish to stub class \space2\B and so my unit test file for class \space1\A looks like this:

namespace space2 {
     class B {
        function xyz(){
            // this function and this class are just fakes to prevent the loading of their real counterparts
        }
     }
}

namespace {
   class testA extends PHPUnit_Framework_TestCase {
       // test code here
   } 
}

So the problem is that PhpStorm sees this duplicate class declaration of class B and highlights it as an error.
Is there a way I can prevent this difficulty?

Thanks!

Update: currently I'm doing this using the eval function, but it far offends my taste in good code, so if you were going to offer this as a solution, please don't.