Telerik JustMock
[TestMethod]
public void ShouldAssertCustomValueForDateTimeNow()
{
// Arrange
Mock.Arrange(() => DateTime.Now).Returns(new DateTime(1900, 4, 12));
// Act
var now = DateTime.Now;
// Assert
Assert.AreEqual(1900, now.Year);
Assert.AreEqual(4, now.Month);
Assert.AreEqual(12, now.Day);
}