public void CheckEasterSunday()
{
var easterSunday = DateSystem.EasterSunday(1900);
Assert.AreEqual(new DateTime(1900, 4, 15), easterSunday);
easterSunday = DateSystem.EasterSunday(2014);
Assert.AreEqual(new DateTime(2014, 4, 20), easterSunday);
easterSunday = DateSystem.EasterSunday(2015);
Assert.AreEqual(new DateTime(2015, 4, 5), easterSunday);
easterSunday = DateSystem.EasterSunday(2016);
Assert.AreEqual(new DateTime(2016, 3, 27), easterSunday);
easterSunday = DateSystem.EasterSunday(2017);
Assert.AreEqual(new DateTime(2017, 4, 16), easterSunday);
easterSunday = DateSystem.EasterSunday(2018);
Assert.AreEqual(new DateTime(2018, 4, 1), easterSunday);
easterSunday = DateSystem.EasterSunday(2019);
Assert.AreEqual(new DateTime(2019, 4, 21), easterSunday);
easterSunday = DateSystem.EasterSunday(2020);
Assert.AreEqual(new DateTime(2020, 4, 12), easterSunday);
easterSunday = DateSystem.EasterSunday(2200);
Assert.AreEqual(new DateTime(2200, 4, 6), easterSunday);
}