public void OptionAll() { // Option with value var optionInt = Option <int> .Some(12); Assert.IsTrue(optionInt.All(intValue => intValue == 12)); Assert.IsFalse(optionInt.All(intValue => intValue == 13)); // Empty option Option <int> emptyOptionInt = Option.None; Assert.IsFalse(emptyOptionInt.All(intValue => intValue == 12)); // ReSharper disable once ReturnValueOfPureMethodIsNotUsed Assert.Throws <ArgumentNullException>(() => optionInt.All(null)); }