public void CloseTo() { // Sometimes it's handy to have some leniancy on DateTimes in tests // Particularly if you've got something that hits the database! var firstDate = new DateTime(2018, 03, 07, 19, 00, 00); var secondDate = new DateTime(2018, 03, 07, 19, 30, 25); secondDate.Should().BeCloseTo(firstDate, 30.Minutes()); // Okay so 30 minutes might be an extreme example, but you could do ms too! var thirdDate = new DateTime(2018, 03, 07, 19, 00, 00).AddMilliseconds(4); firstDate.Should().BeCloseTo(firstDate, FILL_ME_IN.Milliseconds()); // Change FILL_ME_IN to make this pass }