@Test
    public void testSplitDanglingKey1() {
        Map<String, String> kvMap = splitKv("f1", '&',
                '=', null, null);
        Assert.assertEquals(null, kvMap.get("f1"));
    }
Unit tests for kv splitting and concating.
inlong-sort/sort-formats/format-row/format-kv/src/test/java/org/apache/inlong/sort/formats/kv/KvUtilsTest.java