public void IsValidTests()
{
var attribute = new DateAttribute();
Assert.IsTrue(attribute.IsValid(null)); // Don't check for required
Assert.IsTrue(attribute.IsValid(DateTime.Now));
Assert.IsTrue(attribute.IsValid(DateTime.Now.ToShortDateString()));
Assert.IsTrue(attribute.IsValid("12/31/2010"));
Assert.IsFalse(attribute.IsValid(12));
Assert.IsFalse(attribute.IsValid("12.90"));
Assert.IsFalse(attribute.IsValid("February 24th"));
Assert.IsFalse(attribute.IsValid("yesterday"));
Assert.IsFalse(attribute.IsValid("80/80/2011"));
}