}

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

        assertEquals(10L, callback1.getDocumentSize());
        assertEquals(500L, callback1.getExecuteTime());

        assertEquals(20L, callback2.getDocumentSize());