Enough RSpec

How to force the user as the serializer’s scope:

  # spec/serializers/book_serializer_spec.rb

  RSpec.describe BookSerializer do
    subject(:serialized_book) { serialize(book, scope: user) }

    let(:user) { create :user }
    let(:book) { ... }

    # test stuff
  end

Based on how you define the it part, different behaviors are to be expected:

  # spec/serializers/things_controller_spec.rb

  RSpec.describe ThingsController do
    subject { post :create, params: params }

    # Implicitly calls subject
    it { is_expected.to redirect_to(thing_path(Thing.last)) }

    # Explicitly call subject
    it "redirects to the new thing's show" do
      expect(subject).to redirect_to(thing_path(Thing.last))
    end

    # Does not call subject
    # For this test to work, a before { subject } is needed
    it 'has correct flash message' do
      expect(flash[:notice]).to eq "The thing has been created."
    end
  end

Fixtures

Sometimes, it’s easier to return an OpenStruct with the ad hoc attributes, than relying on factories. Especially if these are crippled with complicated setup or if you don’t need a full factory for the return.

Just wrote this for mocking the return value of a facade sub-class (SomeDomainName::FacadeTo3rdPartyAPI::Response):

    let(:expected_response) do
      OpenStruct.new(content: "art, renaissance, Giotto")
    end