def METHOD_NAME(self, backend_db):
    test_firmware = create_test_firmware(device_class='test class', device_name='test device', vendor='test vendor')
    backend_db.add_object(test_firmware)
    rv = self.test_client.get('/rest/firmware/invalid%20uid', follow_redirects=True)
    assert b'No firmware with UID invalid uid' in rv.data