'Check that each error gets its very own url_name'

def test_unique_url_names(self):

    bad_xml = '<sequential    display_name="oops"><video    url="hi"></sequential>'
    bad_xml2 = '<sequential    url_name="oops"><video    url="hi"></sequential>'
    system = self.get_system()
    descriptor1 = system.process_xml(bad_xml)
    descriptor2 = system.process_xml(bad_xml2)
    self.assertNotEqual(descriptor1.location, descriptor2.location)
    bad_xml = '<vertical    display_name="abc"><problem    url_name="exam1:2013_Spring:abc"/></vertical>'
    bad_xml2 = '<vertical    display_name="abc"><problem    url_name="exam2:2013_Spring:abc"/></vertical>'
    descriptor1 = system.process_xml(bad_xml)
    descriptor2 = system.process_xml(bad_xml2)
    self.assertNotEqual(descriptor1.location, descriptor2.location)
