Ruby: const_set outside the block?

Question

I want to mock a class with Ruby .

How to write a method that will take into account boilerplate code?

The following code:

module Mailgun end module Acani def self.mock_mailgun(mock) temp = Mailgun const_set(:Mailgun, mock) p Mailgun yield ensure const_set(:Mailgun, temp) end end Acani.mock_mailgun('mock') { p Mailgun } 

prints:

 "mock" Mailgun 

What's going on here? Why is Mailgun its original value inside the block? Is this related to Ruby bindings?

Ruby version: 2.1.1p76

Answer 1

Try to put Object. before each const_set .

The code in the question is simplified. Here is the relevant code:

Test / test_helper.rb

 require 'minitest/autorun' module Acani def self.const_mock(const, mock) temp = const_get(const) const_set_silent(const, mock) yield ensure const_set_silent(const, temp) end private def self.const_set_silent(const, value) temp = $VERBOSE $VERBOSE = nil Object.const_set(const, value) ensure $VERBOSE = temp end end 

Test / web_test.rb

 require 'test_helper' require 'rack/test' require_relative '../web' class AppTest < MiniTest::Test include Rack::Test::Methods def app Sinatra::Application end def test_password_reset post '/users', {email: ' [e-mail] ', password: 'password1'} mailgun_mock = MiniTest::Mock.new mailgun_mock.expect(:send, 200, [Hash]) Acani.const_mock(:Mailgun, mailgun_mock) do post '/password_resets', {email: ' [e-mail] '} end mailgun_mock.verify assert_equal 201, last_response.status end end