Rhino Mocks - mocking a method whose return value changes (even when passed the same parameter) with multiple calls

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));

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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.

Simply use

mock.Expect(m=>m.SecondsSinceStarted).Return(1).Repeat.Once();
mock.Expect(m=>m.SecondsSinceStarted).Return(2).Repeat.Once();

This will return 1 during the first call, and 2 during the second call. At least in Rhino Mocks 3.6.0.0.