How would you automate generating a MakeSut(out ...) method from any constructor?

[szalapski]

Given any constructor of a class I want to test, such as:

    public MyService(IFooStore store, IBarService service, IModeratelyLongDependencyName dependency3, ...)
    {
       ...
    }

Can you think of a good way to automatically generate a MakeSut method like the following? I think this is the most tedious part of writing tests for me.

private static MyService MakeSut(
    out Mock<IFooStore> mockStore,
    out Mock<IBarService> mockService,
    out Mock<IModeratelyLongDependencyName> mockDependency3,
    ... )
{ 
  mockStore = new();
  mockService = new();
  mockDependency3 = new();

 return new MyService (mockStore.Object,
     mockStore.Object,
     mockService.Object,
     mockDependency3 .Object,
     ...
);

I have found this to be a good pattern, as the out-parameters let me Setup what I want and ignore what I don't care about when doing non-strict tests. Having this method with the out parameters lets me instantiate all manner of different SUTs easily like...

// arrange
MyService sut = MakeSut(out var mockStore,  out _, out _, ...);
mockStore.Setup(s => s.GetFoo(It.IsAny<int>())).ReturnsAsync(new Foo(){...});

// act
sut.DoTheThing();

// assert
mockStore.Verify(...);

I've explored doing this using Resharper's Custom Patterns, but it seems too limited to accomplish such a thing. So how would you go about writing something that could generate the code for such a MakeSut method from any constructor?

(Or am I barking up the wrong tree and you know of a better pattern to instantiate SUTs with all dependencies mocked and every mock available for .Setup?)

[kzu]

Hm... you may be onto something here. I guess a source generator could emit that for you...