// Test empty ID
        EmptySearchLogEvent emptyEvent = new EmptySearchLogEvent();
        assertEquals("", emptyEvent.getId());
    }

    // Test getVersionNo method
    public void test_getVersionNo() {
        // Test normal version
        TestSearchLogEvent event = new TestSearchLogEvent("id", 5L, "search");
        assertEquals(Long.valueOf(5L), event.getVersionNo());

        // Test version update