Is there a way to get recursive mocks on a class return value with NSubstitute

Question

NSubstitute says this in its docs:

methods that return an interface [...] will automatically return substitutes themselves.

That is enough usually. However, when I do this:

TestMethod:

IUnityContainer unity = Substitute.For<IUnityContainer>();
MyMethod(unity);

Actual Method:

    public void MyMethod(IUnityContainer container)
    {
        this.container = container;

        myObject = container.Resolve<ISomeObject>();

        myObject.CallSomeMethod();
    }

The Resolve Method returns a class. So it is not mocked. That means I get null in myObject and a null reference exception when I call CallSomeMethod;

It would be nice if I could just get a class returned that is a mock (that is unless I have overridden that interface specifically).

Is there any way to get this using NSubstitute?

Won't `IUnityContainer.Resolve` return a `T`? So if `T` is an interface `ISomeObject`, NSubstitute should return an mocked `ISomeObject` if you call `container.Resolve()`. It's not doing this? — David Tchepak, May 16 '12 at 01:41

David Tchepak · Accepted Answer · 2012-05-16T04:18:42.347

2

If ISomeObject is an interface this should work fine. If you want to get auto-substitute classes, the class needs to have a default constructor, and have all it's public members declared as virtual.

The following tests pass for me:

public interface IFactory { T Resolve<T>(); }
public interface ISomeObject { void CallSomeMethod(); }

public class Tests
{
    [Test]
    public void Example()
    {
        var factory = Substitute.For<IFactory>();
        MyMethod(factory);
    }
    public void MyMethod(IFactory container)
    {
        var myObject = container.Resolve<ISomeObject>();
        myObject.CallSomeMethod();
    }
}

edited May 16 '12 at 04:18

answered May 16 '12 at 02:00

David Tchepak

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4

Turns out IUnityContainer.Resolve() is an extension method. I am guessing NSubstitute does not do anything for extension methods... – Vaccano May 16 '12 at 18:54
2

Ah, nicely found. Yes, NSub won't intercept ext/static methods. I would suggest not marking this answer as correct, as the real answer is the one you found: it won't work on static/extension methods. – David Tchepak May 17 '12 at 01:12

Is there a way to get recursive mocks on a class return value with NSubstitute

1 Answers1