public void WhenSubtractTimeSpanCalled_ExpectSameValueReturned()
        {
            // Arrange
            var now = DateTime.Now;
            var subtractedTimeSpan = TimeSpan.FromDays(15);
            var expected = now.Subtract(subtractedTimeSpan);

            // Act
            var target = new DateTimeWrap(now);
            var actual = target.Subtract(subtractedTimeSpan);

            // Assert
            actual.DateTimeInstance.Should().Equal(expected);
        }
        public void WhenSubtractDateTimeCalled_ExpectSameValueReturned()
        {
            // Arrange
            var now = DateTime.Now;
            var subtractedDate = new DateTime(2000, 1, 1);
            var expected = now.Subtract(subtractedDate);

            // Act
            var target = new DateTimeWrap(now);
            var actual = target.Subtract(new DateTimeWrap(subtractedDate));

            // Assert
            actual.Should().Equal(expected);
        }