Question

I’m using Moq library. I’m mocking up an instance that does all regular CRUD functionality. I would like to set it up in a way to allow only one Delete(x) call over some object and all consecutive calls to Delete(x) of the same object should return an Exception.

My Delete() method returns void.

How do I do that?

Some code

mock = new Mock<ITest>();
mock.Setup(m => m.Delete(1));
mock.Setup(m => m.Delete(3)).Throws<Exception>();
...

Answer 1

Let the code talk 🙂

    public interface ITest
    {
        void Delete(int x);
    }

    [TestMethod]
    [ExpectedException(typeof(InvalidOperationException))]
    public void TestMethod1()
    {
        HashSet<int> deleted = new HashSet<int>();

        var mock = new Mock<ITest>();
        mock.Setup(m => m.Delete(It.Is<int>(x => deleted.Contains(x))))
            .Throws(new InvalidOperationException("already deleted"));
        mock.Setup(m => m.Delete(It.Is<int>(x => !deleted.Contains(x))))
            .Callback<int>(x => deleted.Add(x));

        mock.Object.Delete(1);
        mock.Object.Delete(1);
    }