I want to spy on a decorator using Sinon to ensure the string I am passing to it is correct

export class MyClass {
  @example('mystring')
  async myMeth() {
    console.log('do stuff')
  }
}

Originally I used reflection on the myMeth method of MyClass to see what the decorator was doing to the method but I realised this is testing the internals of the decorator and the decorator itself. The decorator already has tests.

I just want to ensure there are no typos in the 'mystring` I am passing.

Spying on functions with sinon is easy;

mySpy = Sinon.spy(MyClass, 'myMeth')

And decorators are in essence just functions that wrap functions, but I am totally clueless on how to achieve this.