String result = StringUtil.join("   ", "spaced", "out");
        assertEquals("spaced   out", result);
    }

    @Test
    @DisplayName("Should handle elements containing delimiter")
    void testJoinElementsContainingDelimiter() {
        String result = StringUtil.join(",", "a,b", "c,d", "e,f");
        assertEquals("a,b,c,d,e,f", result);
    }

    @Test
    @DisplayName("Should handle empty array")