public void Should_provide_correct_hash_codes()
{
var id1 = Guid.NewGuid();
var id2 = Guid.NewGuid();
var user1a = new DO(id1, 1);
var user1b = new DO(id1, 2);
var user2 = new DO(id2, 2);
Assert.Equal(user1a.GetHashCode(), user1b.GetHashCode());
Assert.NotEqual(user1a.GetHashCode(), user2.GetHashCode());
}