assertEquals("t1,s1,r1,p1", new KuromojiItem(1, "t1", "s1", "r1", "p1").toLineString());
        assertEquals("t\"\"1,s\"\"1,r\"\"1,p\"\"1", new KuromojiItem(1, "t\"1", "s\"1", "r\"1", "p\"1").toLineString());
        assertEquals("\"t,1\",\"s,1\",\"r,1\",\"p,1\"", new KuromojiItem(1, "t,1", "s,1", "r,1", "p,1").toLineString());
        assertEquals("\"t\"\",1\",\"s\"\",1\",\"r\"\",1\",\"p\"\",1\"",

        // When newInput is set back to null
        item.setNewInput(null);
        assertEquals("original", item.toLineString());
    }

    public void test_toLineString_withEmptyInput() {
        // Test toLineString with empty original input
        StopwordsItem item = new StopwordsItem(1, "");
        assertEquals("", item.toLineString());

        item.setNewInput("new");

        assertEquals("a=>b", new SynonymItem(1, new String[] { "a" }, new String[] { "b" }).toLineString());
        assertEquals("A,a=>B,b", new SynonymItem(1, new String[] { "A", "a" }, new String[] { "B", "b" }).toLineString());
        assertEquals("A,a", new SynonymItem(1, new String[] { "A", "a" }, new String[] { "A", "a" }).toLineString());

        assertEquals("", item.toLineString());

        // Test with item created with id=0
        ProtwordsItem newItem = new ProtwordsItem(0, "newword");
        assertEquals("newword", newItem.toLineString());
    }

    public void test_toLineString_withEmptyInput() {
        // Test toLineString with empty input
        ProtwordsItem item = new ProtwordsItem(1, "");
        assertEquals("", item.toLineString());

    }

    public void test_toLineString() {
        assertEquals("aaa=>a", new StemmerOverrideItem(1, "aaa", "a").toLineString());
        assertEquals("=>", new StemmerOverrideItem(1, "", "").toLineString());
    }

        // Should use new values when updated
        assertEquals("new1,new2,new3=>newOutput", item.toLineString());
    }

    public void test_toLineString_withSingleInput() {
        String[] inputs = { "single" };
        CharMappingItem item = new CharMappingItem(1L, inputs, "output");

        assertEquals("single=>output", item.toLineString());
    }

    public void test_toLineString_withEmptyInputs() {

        public KuromojiItem write(final KuromojiItem oldItem) {
            try {
                if (item == null || item.getId() != oldItem.getId() || !item.isUpdated()) {
                    writer.write(oldItem.toLineString());
                    writer.write(Constants.LINE_SEPARATOR);
                    return oldItem;
                }
                if (!item.equals(oldItem)) {

        public SynonymItem write(final SynonymItem oldItem) {
            try {
                if (item == null || item.getId() != oldItem.getId() || !item.isUpdated()) {
                    writer.write(oldItem.toLineString());
                    writer.write(Constants.LINE_SEPARATOR);
                    return oldItem;
                }
                if (!item.equals(oldItem)) {

        public CharMappingItem write(final CharMappingItem oldItem) {
            try {
                if (item == null || item.getId() != oldItem.getId() || !item.isUpdated()) {
                    writer.write(oldItem.toLineString());
                    writer.write(Constants.LINE_SEPARATOR);
                    return oldItem;
                }
                if (!item.equals(oldItem)) {

    }

    /**
     * Converts this item to a string representation for writing to file.
     * @return the string representation of this item
     */
    public String toLineString() {
        if (isUpdated()) {
            return StringUtils.join(newInput);
        }
        return StringUtils.join(input);
    }