Testing API with RSpec

be_a_valid_api_response.rb

RSpec::Matchers.define :be_a_valid_api_response do
  match do |json_response|
    json_response['version'] == '1.0' &&
      json_response['response']['status'] == 0 &&
      json_response['response']['reason'] == 'Request successfully processed'
  end
end

commons_specs.rb

it "returns a 200 HTTP status" do
  expect(response).to be_success
end

it "returns a valid JSON response" do
  expect(json).to be_a_valid_api_response
end

continents.json

{
  "version": "1.0",
    "response": {
      "status": 0,
      "reason": "Request successfully processed"
    },
    "continents": [{
      "id": "528ce3d151f3fc3ef3000002",
      "name": "Europe",
      "image": "http://domain.tdl/path/to/image.png"
    }, {
      "id": "528ce3d151f3fc3ef3000012",
      "name": "Asia",
      "image": "http://domain.tdl/path/to/image.png"
    }]
}

continents_spec.rb

require 'spec_helper'

describe 'Continents API' do
  describe 'continents.json' do

    before do
      %w[Europe Asia America Africa Oceania].each do |name|
        FactoryGirl.create :continent, name: name
      end

      get '/api/v1/roaming/continents.json'
    end

    it "returns a 200 HTTP status" do
      expect(response).to be_success
    end

    it "returns a valid JSON response" do
      expect(json).to be_a_valid_api_response
    end

    it "returns the right number of continents" do
      expect(json['continents'].lenght).to eq(5)
    end

    it "returns the continents with the right format" do
      json['continents'].each do |continent|
        expect(continent).to match_the_format(
          "id", "name", "image")
      end
    end
  end
end

continents_spec_01.rb

require 'spec_helper'

describe 'Continents API' do
  describe 'continents.json' do
    it "returns a 200 HTTP status" do
      get '/api/v1/roaming/continents.json'

      expect(response).to be_success
    end
  end
end

continents_spec_02.rb

...

it "returns a valid JSON response" do
  get '/api/v1/roaming/continents.json'

  json = JSON.parse(response.body)
  expect(json['version']).to eq("1.0")
  expect(json['response']['status']).to eq(0)
  expect(json['response']['reason']).to eq("Request successfully processed")
end

...

continents_spec_03.rb

...

before do
  get '/api/v1/roaming/continents.json'
end

...

continents_spec_04.rb

require 'spec_helper'

describe 'Continents API' do
  describe 'continents.json' do

    before do
      get '/api/v1/roaming/continents.json'
    end

    it "returns a 200 HTTP status" do
      expect(response).to be_success
    end

    it "returns a valid JSON response" do
      expect(json).to be_a_valid_api_response
    end
  end
end

continents_spec_05.rb

...

before do
  %w[Europe Asia America Africa Oceania].each do |name|
    FactoryGirl.create :continent, name: name
  end

  get '/api/v1/roaming/continents.json'
end

...

it "returns the right number of continents" do
  expect(json['continents'].lenght).to eq(5)
end

...

continents_spec_06.rb

...

it "returns the continents with the right format" do
  json['continents'].each do |continent|
    expect(continent.keys).to eq(["id", "name", "image"])
  end
end

...

continents_spec_07.rb

require 'spec_helper'
require 'set'

...

it "returns the continents with the right format" do
  json['continents'].each do |continent|
    expect(continent.keys.to_set).to eq(
      ["id", "name", "image"].to_set
    )
  end
end

...

json_helper.rb

module Request
  module JsonHelpers
    def json
      @json ||= JSON.parse(response.body)
    end
  end
end

RSpec.configure do |config|
  config.include Requests::JsonHelpers, type: :request
end

match_the_format.rb

RSpec::Matchers.define :match_the_format do |*expected_format|
  require 'set'

  match do |json_resource|
    json_resource.keys.to_set == expected_format.to_set
  end
end

shared_example.rb

shared_example "a successful api request" do
  it "returns a 200 HTTP status" do
    expect(response).to be_success
  end

  it "returns a valid JSON response" do
    expect(json).to be_a_valid_api_response
  end
end

using_shared_example_spec.rb

require 'spec_helper'

describe 'Continents API' do
  describe 'continents.json' do

    ...

    it_behaves_like "a successful api request"

    ...
  end
end