c# unit test child method calls parameters

here is my c# code.

I m not sure I I should verify that Getmethods called with correct parameters.

Public IList<Products> GetProducts(string categoryId)

{
vat items = _service.Get(new Category{id=categoryId, flag=true);

return items:
}

e.g. it was called a with Category class object with parameter flag as true and Id as passed if.