for rails apps that are too complicated to be tested with builtin integration test
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itg_test - simple integration test framework


For Rails apps that are too complicated to be tested with the builtin integration test, such as apps that spawn threads that update the same database table.
For example, we have this piece of code in our app

1  class MyController < ApplicationController
2    def some_method
3      SomeModel.find(id).update_column :a_column, false
4{ AnotherModel.do_something }
5    end
6  end
8  class AnotherModel < ActiveRecord::Base
9    def do_something
10     SomeModel.find(id).update_column :a_column, true
11   end
12 end
14 # Rails built-in integration test
15 class MyIntegrationTest < ActionDispatch::IntegrationTest
16   test '' do
17     get '/some_method'
18     assert_response :success
19     sleep(1) # wait for the thread in MyController to finish
20     assert SomeModel.find(id).a_column # assertion fails with a false value :(
21   end
22 end

Our integration test will fail in line 20 no matter how long we waited for in line 19, because the spawned thread can never update the column in line 10. The reason is because Rails essentially allows only one thread to access the database at a time when running integration tests. itg_test overcomes this obstacle by simply starting a server and a client in separate processes.


Add gem 'itg_test' in your app's Gemfile, and run bundle install


  • Create a itg folder under Rail's default test folder by running mkdir test/itg. Now your test directory structure should look something like

    $ls test

    fixtures functional integration itg test_helper.rb unit

  • Write integration tests as you would with Rail's default integration test framework. Remember to place them under the itg folder instead of Rail's default integration folder.
    For example, create test/itg/your_app_test.rb with the following contents

    require 'itg_test'
    class YourAppTest < ItgTest::TestCase
      test 'a complete test' do
        get '/peanuts'
        assert_select 'h3 p:nth-child(3)', 'very yummy'
  • Run your itg_test tests with rake test:itg
  • itg_test supports the common Rails integration test helpers, including assert_equal, assert_difference and assert_select etc.
  • You might find the following script that runs all Rails and itg_test tests in one shot handy desc "all tests" task 'test:all' => %w[test test:itg] do end


  • awaw fumin (@awawfumin)


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