Simplify the way we explain how to test cookies in controller

[benoittgt]

The previous documentation was old and was not clear enough to help
developers to understand properly how to test cookies inside a
controller test. Since then it is much easier to test cookies if you
stick to cookies and don't use response.cookies.

You can use response.cookies when you don't change cookies inside your
test.

def show
  cookies["user_name"] = nil
  head 200
end

RSpec.describe SignOutsController, type: :request do
  describe 'GET /signout' do
    it "clear cookie value" do
      get "/sign_out"

      expect(response.cookies["user_name"]).to eq(nil)
    end
  end
end

Use cookies to set and expect when you set cookies inside your test

def show
  cookies.delete("user_name")
  head 200
end

RSpec.describe SignOutsController, type: :request do
  describe 'GET /signout' do
    it "clear cookie value" do
      cookies["user_name"] = "Sam"

      get "/sign_out"

      expect(cookies["user_name"]).to eq("")
    end
  end
end

This is the preferred way.

Related:

• Unable to set cookies to be passed in request specs #1993

[benoittgt]

Can we stick rubocop version...? It is failing way too often. But with #2126 it should be ok.

[JonRowe]

LGTM, merge on green!