'Calling /json/subscriptions/exist on a stream to which you are not
subbed should return that it exists and that you are not subbed.'

def test_successful_subscriptions_exists_not_subbed(self):

    all_stream_names = [stream.name for stream in Stream.objects.filter(realm=self.test_realm)]
    streams_not_subbed = list((set(all_stream_names) - set(self.streams)))
    self.assertNotEqual(len(streams_not_subbed), 0)
    self.helper_subscriptions_exists(streams_not_subbed[0], True, False)
