public void ConvertDateFromMonthFirstToYearFirst() { var date = "12/31/1997"; var newDate = RegexUtilities.ConvertDateFromMonthFirstToYearFirst(date, '/', '-'); Assert.AreEqual("1997-12-31", newDate); date = "12-31-97"; newDate = RegexUtilities.ConvertDateFromMonthFirstToYearFirst(date, '-', '/'); Assert.AreEqual("97/12/31", newDate); date = "The party lasted from 12/31/1997 to 1/1/2011"; newDate = RegexUtilities.ConvertDateFromMonthFirstToYearFirst(date, '/', '-'); Assert.AreEqual("The party lasted from 1997-12-31 to 2011-1-1", newDate); }