String decoded = new String(BaseEncoding.base64().decode(encoded), StandardCharsets.UTF_8);

        assertEquals(unicodeString, decoded);
    }

    @Test
    public void test_special_characters_base64_encoding() {
        // Test that special characters are properly encoded/decoded
        String specialString = "******@****.***";

Shinsuke Sugaya <******@****.***> 1773442886 +0900