Comment by jayd16

If you want to enforce things, use an interface. If you want to accept anything that fits use a delegate.

I'm not sure I understand your use case where you need to conflate the two. You want to enforce the contract but with arbitrary method names?

I suppose you could wire up something like this but it's a bit convoluted.

    interface IFoo {
     string F(String s);
    }
    
    class Bar {
     public string B(String s){
      return "";
     }
    }

    // internal class, perhaps in your test framework
    class BarContract : Bar, IFoo {
     public string F(string s) => B(s);
    }