Ruby:const_set 外 block ？

Question

我要mock a class with Ruby .

如何编写处理样板代码的方法？

以下代码:

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 }

打印:

"mock"
Mailgun

这是怎么回事？为什么 Mailgun 是 block 内的原始值？这与 Ruby 绑定(bind)有关吗？

ruby 版本:2.1.1p76

Answer 1

尝试将 Object. 放在每个 const_set 之前。

问题中的代码被简化了。以下是相关代码:

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: 'user1@gmail.com', password: 'password1'}

    mailgun_mock = MiniTest::Mock.new
    mailgun_mock.expect(:send, 200, [Hash])

    Acani.const_mock(:Mailgun, mailgun_mock) do
      post '/password_resets', {email: 'user1@gmail.com'}
    end

    mailgun_mock.verify
    assert_equal 201, last_response.status
  end
end