[rjbwork]

>Isn't this just mostly an issue with mock testing in C#

Yes. You have two choices: Interface implemented once, or virtual on all your public members.

I personally think Interface is the sane choice.

Would be nice if the .NET devs let us mock POCO's though...

[hadrien01]

You can mock (well, "fake") POCOs with packages like AutoFixture that use reflection to generate mostly fake data, depending on what you need. You don't need interfaces or virtual, but you do need public getters unfortunately.