public static String escapeString(String str) {
    return escapeString(str, ESCAPE_CHAR, COMMA);
  }
@Test (timeout = 30000)
  public void testEscapeString() throws Exception {
    assertEquals(NULL_STR, StringUtils.escapeString(NULL_STR));
    assertEquals(EMPTY_STR, StringUtils.escapeString(EMPTY_STR));
    assertEquals(STR_WO_SPECIAL_CHARS,
        StringUtils.escapeString(STR_WO_SPECIAL_CHARS));
    assertEquals(ESCAPED_STR_WITH_COMMA,
        StringUtils.escapeString(STR_WITH_COMMA));
    assertEquals(ESCAPED_STR_WITH_ESCAPE,
        StringUtils.escapeString(STR_WITH_ESCAPE));
    assertEquals(ESCAPED_STR_WITH_BOTH2, 
        StringUtils.escapeString(STR_WITH_BOTH2));
  }