### Question:
DateDetector { public static String detectDateFormat( String dateString ) { return detectDateFormat( dateString, null ); } private  DateDetector(); static String getRegexpByDateFormat( String dateFormat ); static String getRegexpByDateFormat( String dateFormat, String locale ); static String getDateFormatByRegex( String regex ); static String getDateFormatByRegex( String regex, String locale ); static Date getDateFromString( String dateString ); static Date getDateFromString( String dateString, String locale ); static Date getDateFromStringByFormat( String dateString, String dateFormat ); static String detectDateFormat( String dateString ); static String detectDateFormat( String dateString, String locale ); static String detectDateFormatBiased( String dateString, String locale, String desiredKey ); static BidiMap getDateFormatToRegExps( String locale ); static boolean isValidDate( String dateString, String dateFormat ); static boolean isValidDate( String dateString ); static boolean isValidDateFormatToStringDate( String dateFormat, String dateString ); static boolean isValidDateFormatToStringDate( String dateFormat, String dateString, String locale );  }### Answer:
@Test public void testDetectDateFormat() { assertEquals( SAMPLE_DATE_FORMAT, DateDetector.detectDateFormat( SAMPLE_DATE_STRING, LOCALE_es ) ); assertNull( DateDetector.detectDateFormat( null ) ); }