public void Parse_PropertyIsIEnumerableOfInt_PropertyIsSetCorrect(string argValue, IEnumerable <int> intValues) { var args = new[] { "-i", argValue }; var parser = new OptionParser(typeof(TestOptionWithIntEnumerable)); // Act var option = parser.Parse(args) as TestOptionWithIntEnumerable; // Assert option .Should() .NotBeNull(); option !.IntValues .Should() .ContainInOrder(intValues); }