chevron-thin-right chevron-thin-left brand cancel-circle search youtube-icon google-plus-icon linkedin-icon facebook-icon twitter-icon toolbox download check linkedin phone twitter-old google-plus facebook profile-male chat calendar profile-male
Ask a question
The Unit Testing Company
Development Resources
Knowledge Base
Welcome to Typemock Community! Here you can ask and receive answers from other community members. If you liked or disliked an answer or thread: react with an up- or downvote.

Related questions

Mock created in Factory class reverts Members.CallOriginal

0 votes
Hi,

I'm trying to create a wrapper class that will wrap a mock and perform some boilerplate functions that I find myself repeating a lot. However, I'm finding that creating a mock inside of such a class causes the default behaviour (when no WhenCalled specified) to revert back to Members.CallOriginal.

I'm just wondering is there a reason for this? And is there a workaround?

Some demonstrative code is below. _InlineMock performs the mocking within the method. _WrapperSuppliedMock performs the same mocking from a wrapper class (this is the one which fails). Finally, _WrapperSuppliedMock performs the same mocking from a static method. 



    [TestFixture][Isolated]
    internal class TestMyUnit
    {
        [Test]
        public void BuzzMyFizz_InlineMock()
        {
            var fizz = Isolate.Fake.Instance<Fizz>();
            Isolate.WhenCalled(() => fizz.OtherMethod()).DoInstead(c => 0);
            fizz.OtherMethod();
            fizz.Buzz();
        }

        [Test]
        public void BuzzMyFizz_WrapperSuppliedMock()
        {
            var fizzMock = new FizzMockWrap();
            fizzMock.Mock.OtherMethod();
            fizzMock.Mock.Buzz();
        }

        [Test]
        public void BuzzMyFizz_Static()
        {
            var fizzMock = FizzMockWrap.MakeFakeStatic();
            fizzMock.OtherMethod();
            fizzMock.Buzz();
        }
    }


    internal class Fizz
    {
        public void Buzz()
        {
            Console.WriteLine("Buzz");
            throw new Exception("Shouldn't get here");
        }

        public int OtherMethod()
        {
            throw new Exception("Shouldn't get here");
        }
    }

    internal class FizzMockWrap
    {
        public Fizz Mock { get; private set; }

        public FizzMockWrap()
        {
            Mock = Isolate.Fake.Instance<Fizz>();
            Isolate.WhenCalled(() => Mock.OtherMethod()).DoInstead(c => 0); // uncomment this line
        }

        public static Fizz MakeFakeStatic()
        {
            var Mock = Isolate.Fake.Instance<Fizz>();
            Isolate.WhenCalled(() => Mock.OtherMethod()).DoInstead(c => 0);
            Isolate.Swap.NextInstance<Fizz>().With(Mock);
            return Mock;
        }
    }
asked by adante
Report User
 (1.7k points)

3 Answers

0 votes
Hi,

This is an interesting approach, and you stumbled on a limitation in Isolator along the way; as part of Isolator's internal implementation, when you perform a WhenCalled() on a call chain that begins with a live (i.e. non faked) object, fakes are created along the call chain that behave like the real objects. This means that when you performed: 
Isolate.WhenCalled(() => Mock.OtherMethod()...

It caused the getter of the Mock property, which is defined on an object that's not faked (FizzMockWrap) to return a CallOriginal fake, which interfered with the behavior you expected from Buzz() (to return recursive fakes).

Working around this is easy - replace the FizzMockWrap implementation by accessing a field rather than a property. This way we don't override the field's behavior: 
    internal class FizzMockWrap
    {
        private Fizz mock;
        public Fizz Mock { get { return mock; } }

        public FizzMockWrap()
        {
            mock = Isolate.Fake.Instance<Fizz>();
            Isolate.WhenCalled(() => mock.OtherMethod()).DoInstead(c => 0); 
        }

        public static Fizz MakeFakeStatic()
        {
            var staticMock = Isolate.Fake.Instance<Fizz>();
            Isolate.WhenCalled(() => staticMock.OtherMethod()).DoInstead(c => 0);
            Isolate.Swap.NextInstance<Fizz>().With(staticMock);
            return staticMock;
        }
    }


Please let me know if this workaround works for you. I will look into fixing the original issue and avoid overriding the fake instance.

Thanks,
Doron
Typemock Support
answered by doron
Report User
 (17.2k points)
0 votes
Another thing I noticed in your tests is heavy use of DoInstead(); as a shortcut, and for readability, you can use WillReturn() in the situation you describe. Instead of this: 
Isolate.WhenCalled(() => mock.Buzz()).DoInstead(c => 0);

you can use: 
Isolate.WhenCalled(() => mock.Buzz()).WillReturn(0);


Doron
answered by doron
Report User
 (17.2k points)
0 votes
Hi,

This is an interesting approach, and you stumbled on a limitation in Isolator along the way; ...

Working around this is easy - replace the FizzMockWrap implementation by accessing a field rather than a property. This way we don't override the field's behavior:

Please let me know if this workaround works for you. I will look into fixing the original issue and avoid overriding the fake instance.

Thanks,
Doron
Typemock Support


Thanks for the prompt and detailed reply Doron. I'll mull over the explanation a little longer :) but the fix you suggested works perfectly.

Also appreciate the extra tip regarding WillReturn(). I actually use the above wrapper class to provide some convenience methods for simulating autoproperties (this is probably abuse of mocking) in this form: 

class Wrapper
{
   public int SomeProperty { get; set; }

...

   public Wrapper()
{
   Isolate.WhenCalled(() => mock.SomeProperty).DoInstead(c => SomeProperty);
   Isolate.WhenCalled(() => mock.SomeProperty = 0).DoInstead(c => SomeProperty = (int)c.Parameters[0]);
}


Which is why I got into the habit DoInstead so much. Good to be reminded there are simpler ways from time to time.
answered by adante
Report User
 (1.7k points)
...

Products

Help

Company

Community

Contact

Typemock Store (US toll FREE 866–895–4680). Copyright © 2006 Typemock Inc. All rights reserved. Terms of Use.