Use NSubstitute ForPartsOf API and call base class Virtual function

[tim12332000]

NSubstitute ver. 2.0.3 (This is old version) I need use old version . becuase my project not support c# 4.0 yet.

I want to use NSubstitute, ForPartsOf API , and I write a virtual method. but when I called virtual method , it thorw null NullReferenceException. like this:

public class NSubTest
{
    public int GetVal()
    {
        return 1;
    }

    public virtual int VirtualGetVal()
    {
        return 1;
    }
}

TEST:

NSubTest sub = Substitute.ForPartsOf<NSubTest>();
sub.GetVal();
sub.VirtualGetVal();//here get error:

ERROR:

NullReferenceException: Object reference not set to an instance of an object
Castle.Proxies.Invocations.NSubTest_VirtualGetVal.InvokeMethodOnTarget ()
Castle.DynamicProxy.AbstractInvocation.Proceed ()
NSubstitute.Proxies.CastleDynamicProxy.CastleInvocationMapper+<>c__DisplayClass1_0.<Map>b__0 ()
System.Lazy`1[System.Object].CreateValue ()
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.

I know if don't call by base method , it's be worked. like this :

sub.WhenForAnyArgs(x=>x.VirtualGetVal()).DoNotCallBase();
sub.VirtualGetVal().Returns(1);

"BUT" I need call base method when some case , How should I do ?

[GeraldLx]

You probably need to specify your setup more specific. I cannot reproduce the problem.

I made a small project targeting the oldest .NET version supported by NSubstitute 2.0.3 (which is .NET Framework 3.5), added NSubstitute 2.0.3, copied your code and it works. (I dont get this NullReferenceException)