mergedItem.setEmptySource(item2.toEmptyMap());

        // Sum frequencies
        mergedItem.setQueryFreq(item1.getQueryFreq() + item2.getQueryFreq());
        mergedItem.setDocFreq(item1.getDocFreq() + item2.getDocFreq());

        return mergedItem;
    }

    /**
     * Merges readings at a specific index from two reading arrays.
     */

        SuggestItem[] mergedItems = writer.mergeItems(new SuggestItem[] { item1, item2 });

        assertNotNull(mergedItems);
        assertEquals(1, mergedItems.length);
        assertEquals(3, mergedItems[0].getDocFreq());
    }

    @Test
    public void test_mergeItemsWithDifferentTexts() throws Exception {
        String[][] readings1 = new String[1][];
        readings1[0] = new String[] { "test1" };

        String[][] readings = { { "test" } };

        SuggestItem item = new SuggestItem(text, readings, null, 0L, 0L, 1.0f, null, null, null, SuggestItem.Kind.QUERY);

        assertEquals(0L, item.getDocFreq());
        assertEquals(0L, item.getQueryFreq());
    }

    @Test
    public void test_maxFrequencies() {
        String[] text = { "test" };
        String[][] readings = { { "test" } };

        SuggestItem item = SuggestItemSerializer.fromSource(source);

        assertNotNull(item);
        assertEquals("test text", item.getText());
        assertEquals(10L, item.getDocFreq());
        assertEquals(5L, item.getQueryFreq());
        assertEquals(1.5f, item.getUserBoost(), 0.001f);
    }

    @Test
    public void testToJson() {
        String[] text = { "json test" };

        SuggestItem item2 = createItem("text", 20L, 15L, 2.0f);

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

        assertNotNull(merged);
        assertEquals(30L, merged.getDocFreq()); // 10 + 20
        assertEquals(20L, merged.getQueryFreq()); // 5 + 15
        assertEquals(2.0f, merged.getUserBoost(), 0.001f); // max(1.0, 2.0)
    }

    @Test
    public void testMerge_tags() {

        secondLine.put("fields", item.getFields());
        secondLine.put("queryFreq", item.getQueryFreq());
        secondLine.put("docFreq", item.getDocFreq());
        secondLine.put("userBoost", item.getUserBoost());
        secondLine.put("score", (item.getQueryFreq() + item.getDocFreq()) * item.getUserBoost());
        secondLine.put("tags", item.getTags());
        secondLine.put("roles", item.getRoles());

        assertNotNull(items);
        assertTrue(items.size() > 0);
        for (SuggestItem item : items) {
            assertEquals(SuggestItem.Kind.DOCUMENT, item.getKinds()[0]);
            assertEquals(1, item.getDocFreq());
        }
    }

    @Test
    public void test_parseDocumentWithTags() throws Exception {
        Map<String, Object> document = new HashMap<>();
        document.put("content", "テストドキュメント");