NSubstitute .Returns() and Arg,Any<int> How to use the passed parametrers for Subsituted interface

I am NSubstituting for an Interface and Having trouble with the usage of passed Parameters (i,j):

The first two lines 25 and 26 are fine but I am having trouble with 27,,29
I need to use the arguments (i,j) they passed to me.
How might i correctly use NSubstitute?

Here is the Interface I am NSubstituting for:

public interface IGamePieceFactory
   {
      IGamePieceViewModel Create(int i, int j);
      IGamePieceViewModel Create();
   }

>Solution :

To use the values passed into the call for building your return value, you need to use an overloaded version of Returns that takes the arguments as parameters:

mockGameFactory
    .Create(Arg.Any<int>(), Arg.Any<int>())
    .Returns(args => new GamePieceViewModel
    {
        Point = new Point((int)args[0], (int)args[1])
    }

This is detailed here in the documentation in advanced usages:

• https://nsubstitute.github.io/help/return-from-function/

I’d recommend paying special attention to the comment there, however:

Although this is normally a bad practice, there are some situations in which it is useful.

I’d agree that this is usually a bad practice and that you should look into how you are testing if you need to rely on this feature too much.