public void WhenAddMillisecondsCalled_ExpectSameValueReturned()
        {
            // Arrange
            var now = DateTime.Now;
            const int added = 15;
            var expected = now.AddMilliseconds(added);

            // Act
            var target = new DateTimeWrap(now);
            var actual = target.AddMilliseconds(added);

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