String result = StringUtil.join("", "hello", "world");
        assertEquals("helloworld", result);
    }

    @Test
    @DisplayName("Should join with multi-character delimiter")
    void testJoinWithMultiCharDelimiter() {
        String result = StringUtil.join(" - ", "apple", "banana", "cherry");
        assertEquals("apple - banana - cherry", result);
    }

    @Test