// Same object
        assertTrue(item1.equals(item1));

        // Same input value (id doesn't matter)
        assertTrue(item1.equals(item2));
        assertTrue(item1.equals(item3));

        // Different input value
        assertFalse(item1.equals(item4));

        // Null and different class
        assertFalse(item1.equals(null));
        assertFalse(item1.equals("string"));

        String[] text1 = { "item1" };
        String[][] readings1 = { { "read1" } };
        String[] tags1 = { "tag1" };
        String[] roles1 = { "role1" };
        String[] languages1 = { "en" };

        SuggestItem item1 = new SuggestItem(text1, readings1, null, 50L, 100L, 2.0f, tags1, roles1, languages1, SuggestItem.Kind.QUERY);

        String[] text2 = { "item1" }; // Same text for same ID

        // Test reflexivity
        assertTrue(item1.equals(item1));

        // Test symmetry and arrays with different order
        assertTrue(item1.equals(item2));
        assertTrue(item2.equals(item1));

        // Test with different inputs
        assertFalse(item1.equals(item3));
        assertFalse(item3.equals(item1));

        // Test with different output

        // Same object
        assertTrue(item1.equals(item1));

        // Same input, different id
        assertTrue(item1.equals(item2));

        // Different input
        assertFalse(item1.equals(item3));

        // Same id and input
        assertTrue(item1.equals(item4));

        // Null object
        assertFalse(item1.equals(null));

        // Different class

        mergedItem.setFields(mergeStringArrays(item1.getFields(), item2.getFields()));
        mergedItem.setTags(mergeStringArrays(item1.getTags(), item2.getTags()));
        mergedItem.setLanguages(mergeStringArrays(item1.getLanguages(), item2.getLanguages()));
        mergedItem.setRoles(mergeStringArrays(item1.getRoles(), item2.getRoles()));

        // Merge kinds
        mergedItem.setKinds(mergeKinds(item1.getKinds(), item2.getKinds()));

        SuggestItem item1 = createItem("test text", 10L, 5L, 1.0f);
        SuggestItem item2 = createItem("test text", 20L, 15L, 2.0f);

        SuggestItem merged = SuggestItemMerger.merge(item1, item2);

        assertEquals("test text", merged.getText());
    }

    @Test
    public void testMerge_preservesId() {
        SuggestItem item1 = createItem("text", 10L, 5L, 1.0f);

        TestDictionaryItem item1 = new TestDictionaryItem();
        TestDictionaryItem item2 = new TestDictionaryItem();

        item1.id = 100L;
        item2.id = 200L;

        assertEquals(100L, item1.getId());
        assertEquals(200L, item2.getId());

        // Verify they don't affect each other
        item1.id = 300L;
        assertEquals(300L, item1.getId());
        assertEquals(200L, item2.getId());

        // Test that defensive copy handles null arrays correctly
        SynonymItem item1 = new SynonymItem(1, new String[] { "a" }, new String[] { "x" });

        // Set to null
        item1.setNewInputs(null);
        item1.setNewOutputs(null);

        // Should return null, not crash
        assertNull(item1.getNewInputs());
        assertNull(item1.getNewOutputs());
    }

        OptionalEntity<CharMappingItem> result1 = charMappingFile.get(1L);
        assertTrue(result1.isPresent());
        CharMappingItem item1 = result1.get();
        assertEquals(1L, item1.getId());
        assertArrayEquals(new String[] { "a", "b" }, item1.getInputs());
        assertEquals("c", item1.getOutput());

        OptionalEntity<CharMappingItem> result2 = charMappingFile.get(2L);
        assertTrue(result2.isPresent());

    @Test
    public void test_merge_allKinds() {
        String[] text1 = { "test" };
        String[][] readings1 = { { "test" } };
        SuggestItem item1 = new SuggestItem(text1, readings1, null, 0L, 0L, 1.0f, null, null, null, SuggestItem.Kind.QUERY);
        item1.setKinds(new SuggestItem.Kind[] { SuggestItem.Kind.QUERY, SuggestItem.Kind.DOCUMENT });

        String[] text2 = { "test" };
        String[][] readings2 = { { "test" } };