Arguments.of("::", "A::B::C"), Arguments.of("\n", "A\nB\nC"), Arguments.of("\r\n", "A\r\nB\r\nC"));
    }

    @Test
    @DisplayName("Should handle StringBuilder as CharSequence")
    void testJoinWithStringBuilder() {
        StringBuilder sb1 = new StringBuilder("first");
        StringBuilder sb2 = new StringBuilder("second");
        String result = StringUtil.join(",", sb1, sb2);