Multiple calls to a Rhino mocked method return different results

Question

If I want to mock a class that returns a string that is used to determine whether while loop should continue (imagine read while string != null), how can I set the expectation. I have tried the following:

    provider.Reader.Expect(r => r.ReadLine()).Return("1,10,20");
    provider.Reader.Expect(r => r.ReadLine()).Return(null);

but when it is called twice in the same method, it returns the first string on both occasions, whereas I want it to return the second value (null) if called a second time.

Answer 1

I'm not familiar with the syntax you're using. I would write this as:

r.ReadLine();
LastCall.Return("1,10,20").Repeat.Once();
r.ReadLine();
LastCall.Return(null).Repeat.Once();

To ensure that you're specifying the number of times that things are to be repeated. (Don't have Visual Studio to hand, syntax may not be exact.)

Answer 2

I think you can just stick the repeat on the end of the syntax you're currently using.

provider.Reader.Expect(r => r.ReadLine()).Return("1,10,20").Repeat.Once();
provider.Reader.Expect(r => r.ReadLine()).Return(null).Repeat.Once();

or

 provider.Reader.Expect(r => r.ReadLine()).Return("1,10,20").Repeat.Once();
    provider.Reader.Expect(r => r.ReadLine()).Return(null);

if you have any calls beyond 2nd call that you want to use second expectation.