What does assigns mean in rspec

Question

What does that line of code do?

assigns(:articles).should eq([article])

in the following rspec

  describe "GET #index" do
    it "populates an array of articles" do
      article = Factory(:article)
      get :index
      assigns(:articles).should eq([article])
    end

    it "renders the :index view" do
      get :index
      response.should render_template :index
    end
  end

Answer 1

assigns relates to the instance variables created within a controller action (and assigned to the view).

---

to answer your remark in comments, I guess that:

• 1) your index action looks like @articles = Articles.all (I hope you use pagination though)

• 2) prior to the spec block above, you have one article created in db (or I hope you stub db queries in db)

• 1 + 2 => @articles should contain one article, that's your spec expectation

Answer 2

In a controller spec, assigns will take a symbol (e.g. assigns(:variable)) and returns the controller's corresponding instance variable (e.g. @variable in the controller).

So in the question's example, the index method of the controller evidently sets @articles to a list of articles, and assigns merely makes that value available in the spec.

assigns has been moved into a gem: https://github.com/rails/rails-controller-testing.

https://joshfrankel.me/blog/accessing-instance-variables-within-a-rspec-controller-test/