Unit Testing Entity Framework Validation
===

I have written some custom validation for some Entity Framework objects using IValidatableObject and I have added some DataAnnotations to the objects for validation.

I wanted to test that validation is meeting the required validation (ensuring that the custom validation is working and that any changes made keep those Data Annotations etc...) but I can't determine how to run the validation in the unit test without calling SaveChanges (which I don't want to do as if there is an issue and validation doesn't work it would write to the data source)

I wanted to do something like this:

    [TestMethod]
    public void InvalidStartDate_StartDateAfterEndDate()
    {
       var header = new Header()
                        {
                            StartDate = DateTime.Now.AddDays(15),
                            EndDate = DateTime.Now.AddDays(-15)
                        };
       var actual = header.IsValid();
       var expected = false;
       Assert.AreEqual(expected, actual);
    }

Or something like 

    [TestMethod]
    public void InvalidStartDate_StartDateAfterEndDate()
    {
       var header = new Header()
                        {
                            StartDate = DateTime.Now.AddDays(15),
                            EndDate = DateTime.Now.AddDays(-15)
                        };
       var actual = header.GetValidationErrors().Count;
       var expected = 0;
       Assert.AreEqual(expected, actual);
    }

But can't seem to find a way of getting the validation to run without calling save changes, is there a way to do this?