RSpec API controllers testing - ruby-on-rails

Question

At first, sorry for my English :)
I need to realize API controller's tests in Ruby on Rails application (v 4.2.0).
When I do request to GET Advertising Sources I have a json response like this:
{"advertising_sources":[{"id":59,"title":"accusantium"},{"id":60,"title":"assumenda"}]}
JSON response template was defined by front-end developer.
Now I trying to create tests for:
1. JSON size (2 advert sources)
2. included attributes (id, title)
My tests:
it 'returns list of advertising sources' do
expect(response.body).to have_json_size(2)
end
%w(id title).each do |attr|
it "returns json with #{attr} included" do
hash_body = JSON.parse(response.body)
expect(hash_body).to include(attr)
end
end
Failures:
1. Failure/Error: expect(response.body).to have_json_size(2)
expected {"advertising_sources":[{"id":59,"title":"accusantium"},{"id":60,"title":"assumenda"}]} to respond to `has_json_size?`
2. Failure/Error: expect(hash_body).to include(attr)
expected {"advertising_sources" => [{"id" => 71, "title" => "necessitatibus"}, {"id" => 72, "title" => "impedit"}]} to include "id"
Diff:
## -1,2 +1,2 ##
-["id"]
+"advertising_sources" => [{"id"=>71, "title"=>"necessitatibus"}, {"id"=>72, "title"=>"impedit"}],
Can anyone help me to correctify my tests code?
Thanks!

Answer 1

Given the shape of your response and the characteristics you are interested in testing, you can write your tests as follows:
describe 'advertising_sources' do
let(:parsed_response_body) { JSON.parse(response.body) }
let(:advertising_sources) { parsed_response_body['advertising_sources'] }
it 'returns list of advertising sources' do
expect(advertising_sources.size).to eq(2)
end
%w(id title).each do |attr|
it "returns json with #{attr} included" do
advertising_sources.each { |source| expect(source.keys).to include(attr) }
end
end
end
I would personally simplify this even further to:
describe 'advertising_sources' do
let(:parsed_response_body) { JSON.parse(response.body) }
let(:advertising_sources) { parsed_response_body['advertising_sources'] }
it 'returns list of advertising sources' do
expect(advertising_sources.size).to eq(2)
end
it 'includes an id and title for each source' do
advertising_sources.each { |source| expect(source.keys).to match_array(%w(id title)) }
end
end