I'm looking to find out how I can mock a method that returns a different value the second time it is called to the first time. For example, something like this:
public interface IApplicationLifetime
{
int SecondsSinceStarted {get;}
}
[Test]
public void Expected_mock_behaviour()
{
IApplicationLifetime mock = MockRepository.GenerateMock<IApplicationLifetime>();
mock.Expect(m=>m.SecondsSinceStarted).Return(1).Repeat.Once();
mock.Expect(m=>m.SecondsSinceStarted).Return(2).Repeat.Once();
Assert.AreEqual(1, mock.SecondsSinceStarted);
Assert.AreEqual(2, mock.SecondsSinceStarted);
}
Is there anything that makes this possible? Besides implementing a sub for the getter that implements a state machine?
You can intercept return values with the .WhenCalled
method. Note that you still need to provide a value via the .Return
method, however Rhino will simply ignore it if ReturnValue
is altered from the method invocation:
int invocationsCounter = 1;
const int IgnoredReturnValue = 10;
mock.Expect(m => m.SecondsSinceLifetime)
.WhenCalled(mi => mi.ReturnValue = invocationsCounter++)
.Return(IgnoredReturnValue);
Assert.That(mock.SecondsSinceLifetime, Is.EqualTo(1));
Assert.That(mock.SecondsSinceLifetime, Is.EqualTo(2));
Digging around a bit more, it seems that .Repeat.Once()
does indeed work in this case and can be used to achieve the same result:
mock.Expect(m => m.SecondsSinceStarted).Return(1).Repeat.Once();
mock.Expect(m => m.SecondsSinceStarted).Return(2).Repeat.Once();
mock.Expect(m => m.SecondsSinceStarted).Return(3).Repeat.Once();
Will return 1, 2, 3 on consecutive calls.