Assigning out/ref parameters in Moq

Question

Is it possible to assign an out/ref parameter using Moq (3.0)?

I've looked at using Callback(), but Action<> does not support ref parameters because it's based on generics. I'd also preferably like to put a constraint (It.Is) on the input of the ref parameter, though I can do that in the callback.

I know that Rhino Mocks supports this functionality, but the project I'm working on is already using Moq.

Answer 1

Seems like it is not possible out of the box. Looks like someone attempted a solution

See this forum post http://code.google.com/p/moq/issues/detail?id=176

this question http://stackoverflow.com/questions/726630/verify-value-of-reference-parameter-with-moq

Answer 2

For 'out', the following seems to work for me.

public interface IService
{
    void DoIt(out string a);
}

[TestMethod]
public void Test()
{
    var service = new Mock<IService>();
    var a = "output value";
    service.Setup(s => s.DoIt(out a));

    string b;
    service.Object.DoIt(out b);
    Assert.AreEqual("output value", b);
}

I'm guessing that Moq looks at the value of 'a' when you call Setup and remembers it.

For 'ref', I'm looking for an answer also.

I found the following QuickStart guide useful: http://code.google.com/p/moq/wiki/QuickStart