public static String unEscapeString(String str) {
    return unEscapeString(str, ESCAPE_CHAR, COMMA);
  }
@Test (timeout = 30000)
  public void testUnescapeString() throws Exception {
    assertEquals(NULL_STR, StringUtils.unEscapeString(NULL_STR));
    assertEquals(EMPTY_STR, StringUtils.unEscapeString(EMPTY_STR));
    assertEquals(STR_WO_SPECIAL_CHARS,
        StringUtils.unEscapeString(STR_WO_SPECIAL_CHARS));
    try {
      StringUtils.unEscapeString(STR_WITH_COMMA);
      fail("Should throw IllegalArgumentException");
    } catch (IllegalArgumentException e) {
      // expected
    }
    assertEquals(STR_WITH_COMMA,
        StringUtils.unEscapeString(ESCAPED_STR_WITH_COMMA));
    try {
      StringUtils.unEscapeString(STR_WITH_ESCAPE);
      fail("Should throw IllegalArgumentException");
    } catch (IllegalArgumentException e) {
      // expected
    }
    assertEquals(STR_WITH_ESCAPE,
        StringUtils.unEscapeString(ESCAPED_STR_WITH_ESCAPE));
    try {
      StringUtils.unEscapeString(STR_WITH_BOTH2);
      fail("Should throw IllegalArgumentException");
    } catch (IllegalArgumentException e) {
      // expected
    }
    assertEquals(STR_WITH_BOTH2,
        StringUtils.unEscapeString(ESCAPED_STR_WITH_BOTH2));
  }