def test_empty(self):
        """Test empty method to empty and with one event in query."""
        empty_1 = self.kytos_event_buffer.empty()

        event = self.create_event_mock()
        self.kytos_event_buffer._queue.sync_q.put(event)

        empty_2 = self.kytos_event_buffer.empty()

        self.assertTrue(empty_1)
        self.assertFalse(empty_2)