### Question:
DateUtil { public static boolean validateUTCString(String utcDateString) { if (StringUtils.isBlank(utcDateString)) { return false; } Date date = parse(utcDateString, FORMAT_UTC); return null != date; } private  DateUtil(); static Date parseUTC(String dateString); static boolean validateUTCString(String utcDateString); static String formatUTC(Date date); static Date parse(String dateString, String format);  }### Answer:
@Test public void test_validateUTCString_utcdate_true() throws ParseException{ String dateString = "2015-01-22T17:30:00Z"; assertEquals(true, DateUtil.validateUTCString(dateString)); }
@Test public void test_validateUTCString_not_utcdate_false() throws ParseException{ String dateString = "2015-01-22 17:30:00"; assertEquals(false, DateUtil.validateUTCString(dateString)); }
@Test public void test_validateUTCString_emptydate_false() throws ParseException{ String dateString = ""; assertEquals(false, DateUtil.validateUTCString(dateString)); }
@Test public void test_validateUTCString_nulldate_false() throws ParseException{ String dateString = null; assertEquals(false, DateUtil.validateUTCString(dateString)); }