EmptySearchLogEvent emptyEvent = new EmptySearchLogEvent();
        assertEquals("", emptyEvent.getEventType());
    }

    // Test multiple implementations
    @Test
    public void test_multipleImplementations() {
        // Create different implementations
        SearchLogEvent event1 = new TestSearchLogEvent("id1", 1L, "type1");
        SearchLogEvent event2 = new NullSearchLogEvent();

        assertEquals(300L, callback.getExecuteTime());

        // Test commit (should not throw exception)
        callback.commit();
    }

    @Test
    public void test_multiple_implementations() {
        // Test with different implementations to ensure interface contract
        IndexUpdateCallback callback1 = createMockCallback(10, 500);
        IndexUpdateCallback callback2 = createMockCallback(20, 1000);