### Question:
StringUtils { public static String revertIllegalCharsAttribute(final String value) { if (isEmpty(value)) { return value; } return value.replace("&lt;", "<") .replace("&gt;", ">") .replace("&amp;", "&") .replace("&quot;", "\""); } private  StringUtils(); static boolean isEmpty(final String s); static boolean nonEmpty(final String s); static boolean hasNonEmpty(final String... values); static boolean isQuoted(String str); static String createQuotedString(final String str); static String createQuotedStringIfNotNumeric(String str); static String replaceIllegalCharsAttribute(final String value); static String replaceIllegalCharsForDataObjects(final String value); static String revertIllegalCharsAttribute(final String value); static String createUnquotedString(String str);  }### Answer:
@Test public void testRevertIllegalCharsAttribute() { assertSame(EMPTY_STRING, revertIllegalCharsAttribute(EMPTY_STRING)); assertEquals(null, revertIllegalCharsAttribute(null)); assertEquals("< Valid \"&\" Symbols >", revertIllegalCharsAttribute(ENCODED_VALUE)); }