FakeItEasy setting property with no get accessor? - fakeiteasy

Question

I'm trying to use FakeItEasy 2.0.0 to fake a property in a simple interface:
public interface IPerson
{
int Age { set; }
}
Note that I don't have a get accessor. The test I'm trying to write is:
public void SetsAge()
{
var fakePerson = A.Fake<IPerson>();
A.CallToSet(() => fakePerson.Age).To(42).MustHaveHappened();
fakePerson.Age = 42;
}
But the line containing A.CallToSet fails to compile with:
which is fairly self-explanatory, but confusing since I'm not trying to get the property's value.
Do I have to provide a get accessor to get this to compile (even though I don't want a get accessor)? What is the reason that it requires the get accessor in this case (the same compiler error happens when I replace MustHaveHappened with DoesNothing)? Or am I doing something fundamentally wrong?
Or perhaps I shouldn't lose too much sleep over this and do the right thing in the first place?

Answer 1

Do I have to provide a get accessor to get this to compile?
No, you can use
A.CallTo(fakePerson).Where(call => call.Method.Name == "set_Age" &&
call.GetArgument<int>(0) == 42)
.MustHaveHappened();
This is documented in Specifying a call to any method or property.
What is the reason that it requires the get accessor?
The reason is that because you can't use a = in a lamdba expression, there's no easy way to refer to the property setter. In 2.0, we added A.CallToSet to allow you to cheat by using the getter, but of course it only works when there is a getter.
We've not yet come up with an elegant way to refer to a getterless setter, so you have to use the powerful version of A.CallTo above.
Or am I doing something fundamentally wrong?
Well, in addition to the problem with referring to the property, the whole A.CallTo…MustHaveHappend() has to occur after fakePerson.Age = 42, or it will report a failure, because you haven't yet set fakePerson.Age to 42.