SetupSequence in Moq

The cleanest way is to create a Queue and pass .Dequeue method to Returns

.Returns(new Queue<int>(new[] { 0, 1, 1, 1 }).Dequeue);

That's not particulary fancy, but I think it would work:

    var firstTime = true;

    mock.Setup(x => x.GetNumber())
        .Returns(()=>
                        {
                            if(!firstTime)
                                return 1;

                            firstTime = false;
                            return 0;
                        });