Allowing supporting modules hook onto the tests

I'm working on a supporting module to webform and need the thest harness working. I suggest a small modification to the test class so that the initialisation can be done from the original test classes and added tests in the module related tests.
Modification includes allowing the init method to take parameters of modules to be enabled.

  function setUp($added_modules = array()) {

    // Enable Webform.
    $modules = array('webform', 'profile');
    parent::setUp(array_merge($modules, $added_modules));