RSpec: Best way to mock chained DB query

Question

I have the following query:

Trainee.select(:name, :employee_start_date, :exit_date, "count(reviewers.code_review_id) AS reviews_completed")
            .where(user_id: user_ids)
            .joins(:reviewers)
            .where(reviewers: { completion_time: start_date..end_date })
            .group('trainees.user_id').order('reviews_completed DESC')

I am new to rails and rspec and am having a lot of trouble stubbing out this query in my rspec tests. This is what I have so far:

describe '#completed_code_reviews' do
  let(:trainee_service_client) { LeaderboardsService.new('trainee') }
  let(:start_date) { Date.new(2016, 1, 18) - 1.day }
  let(:end_date) { Date.new(2015, 8, 18) + 2.day }
  let(:order) { 'DESC' }

  let(:person_completed_reviews) { 4 }
  let(:select_result) { double('select') }
  let(:where1_result) { double('where1') }
  let(:joins_result) { double('joins') }
  let(:where2_result) { double('where2') }
  let(:group_result) { double('group') }
  let(:trainees_list) { [] }

  context 'a user has no connections' do
    user_ids = []

    it "returns an empty result" do
        allow(Trainee).to receive(:select)
                .with(:name, :devcenter_start_date, :exit_date, 
                    "count(reviewers.code_review_id) AS reviews_completed"
                ).and_return(select_result)

        allow(select_result).to receive(:where).with(user_id: user_ids).and_return(where1_result)

        allow(where1_result).to receive(:joins).with(:reviewers).and_return(joins_result)

        allow(joins_result).to receive(:where)
                .with(reviewers: { completion_time: start_date..end_date.end_of_day })
                .and_return(where2_result)

        allow(where2_result).to receive(:group).with("trainees.user_id").and_return(group_result)

        allow(group_result).to receive(:order).with(person_completed_reviews: order).and_return(trainees_list)


        expect(trainee_service_client.completed_code_reviews(start_date, end_date)).to eq([])
    end
  end
end

Two things:

1) This doesnt actually work.I get: Failure/Error: expect(trainee_service_client.completed_code_reviews(start_date, end_date, [])).to eq(trainee) Double "group" received :order with unexpected arguments expected: ({:person_completed_reviews=>"DESC"}) got: ("reviews_completed DESC")

How do i mock the :order method properly?

2) This setup also seems messy. Is there a more concise way?

B Seven · Accepted Answer · 2016-07-18 23:59:33Z

1

1) You can fix the error with:

allow(group_result).to receive(:order).with("reviews_completed DESC").and_return(trainees_list)

2) This mocking makes no sense to me. Where did you get the idea to do this? Instead, I would create the records you need.

answered Jul 18, 2016 at 23:59

B Seven

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2 Comments

Kaitrono Over a year ago

That did fix the error. I set it up this way because someone showed me an example similar to it. This way you can mock out each step of the query individually and know exactly which point causes an error. That's how my beginner mind understood it at least.

B Seven Over a year ago

I don't know why you would mock each step of the query.

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