How to test model's callback method independently?

Question

I had a method in a model:

class Article < ActiveRecord::Base
  def do_something
  end
end

I also had a unit test for this method:

Answer 1

In the spirit of Sandi Metz and minimalist testing, the suggestion in https://stackoverflow.com/a/16678194/2001785 to confirm the call to a possibly private method does not seem right to me.

Testing a publicly-observable side-effect or confirming an outgoing command message makes more sense to me. Christian Rolle provided an example at http://www.chrisrolle.com/en/blog/activerecord-callback-tests-with-rspec.