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

You can use shoulda-callback-matchers to test existence of your callbacks without calling them.

describe Article do
  it { is_expected.to callback(:do_something).after(:save) }
end

If you also want to test the behaviour of the callback:

describe Article do
  ...

  describe "#do_something" do
    it "gives the article something" do
      @article.save
      expect(@article).to have_something
    end
  end
end