测试中怎么 stub 外部服务 ref: http://qiita.com/xiangzhuyuan/items/9f3301cd30e09369e7d1

file0.rb

# spec/spec_helper.rb
require 'webmock/rspec'
WebMock.disable_net_connect!(allow_localhost: true)

file1.rb

# spec/features/external_request_spec.rb
require 'spec_helper'

feature 'External request' do
  it 'queries FactoryGirl contributors on GitHub' do
    uri = URI('https://api.github.com/repos/thoughtbot/factory_girl/contributors')

    response = Net::HTTP.get(uri)

    expect(response).to be_an_instance_of(String)
  end
end

file2.rb

$ rspec spec/features/external_request_spec.rb
F

Failures:

  1) External request queries FactoryGirl contributors on GitHub
     Failure/Error: response = Net::HTTP.get(uri)
     WebMock::NetConnectNotAllowedError:
       Real HTTP connections are disabled.
       Unregistered request: GET https://api.github.com/repos/thoughtbot/factory_girl/contributors
       with headers {
         'Accept'=>'*/*',
         'Accept-Encoding'=>'gzip;q=1.0,deflate;q=0.6,identity;q=0.3',
         'Host'=>'api.github.com',
         'User-Agent'=>'Ruby'
       }

       You can stub this request with the following snippet:

       stub_request(:get,     "https://api.github.com/repos/thoughtbot/factory_girl/contributors").
     with(:headers => {'Accept'=>'*/*', 'Accept-Encoding'=>'gzip;q=1.0,deflate;q=0.6,identity;q=0.3', 'Host'=>'api.github.com', 'User-Agent'=>'Ruby'}).
     to_return(:status => 200, :body => "", :headers => {})

       ============================================================
     # ./spec/features/external_request_spec.rb:8:in `block (2 levels) in <top (required)>'

Finished in 0.00499 seconds
1 example, 1 failure

file3.rb

# spec/spec_helper.rb
RSpec.configure do |config|
  config.before(:each) do
    stub_request(:get, /api.github.com/).
      with(headers: {'Accept'=>'*/*', 'User-Agent'=>'Ruby'}).
      to_return(status: 200, body: "stubbed response", headers: {})
  end
end

file4.rb

$ rspec spec/features/external_request_spec.rb
.

Finished in 0.01116 seconds
1 example, 0 failures

file5.rb

# spec/spec_helper.rb
RSpec.configure do |config|
  config.before(:each) do
    stub_request(:any, /api.github.com/).to_rack(FakeGitHub)
  end
end

file6.rb

# spec/support/fake_github.rb
require 'sinatra/base'

class FakeGitHub < Sinatra::Base
  get '/repos/:organization/:project/contributors' do
    json_response 200, 'contributors.json'
  end

  private

  def json_response(response_code, file_name)
    content_type :json
    status response_code
    File.open(File.dirname(__FILE__) + '/fixtures/' + file_name, 'rb').read
  end
end

file7.rb

# spec/support/fixtures/contributors.json
[
  {
    "login": "joshuaclayton",
    "id": 1574,
    "avatar_url": "https://2.gravatar.com/avatar/786f05409ca8d18bae8d59200156272c?d=https%3A%2F%2Fidenticons.github.com%2F0d4f4805c36dc6853edfa4c7e1638b48.png",
    "gravatar_id": "786f05409ca8d18bae8d59200156272c",
    "url": "https://api.github.com/users/joshuaclayton",
    "html_url": "https://github.com/joshuaclayton",
    "followers_url": "https://api.github.com/users/joshuaclayton/followers",
    "following_url": "https://api.github.com/users/joshuaclayton/following{/other_user}",
    "gists_url": "https://api.github.com/users/joshuaclayton/gists{/gist_id}",
    "starred_url": "https://api.github.com/users/joshuaclayton/starred{/owner}{/repo}",
    "subscriptions_url": "https://api.github.com/users/joshuaclayton/subscriptions",
    "organizations_url": "https://api.github.com/users/joshuaclayton/orgs",
    "repos_url": "https://api.github.com/users/joshuaclayton/repos",
    "events_url": "https://api.github.com/users/joshuaclayton/events{/privacy}",
    "received_events_url": "https://api.github.com/users/joshuaclayton/received_events",
    "type": "User",
    "site_admin": false,
    "contributions": 377
  }
]

file8.rb

require 'spec_helper'

feature 'External request' do
  it 'queries FactoryGirl contributors on GitHub' do
    uri = URI('https://api.github.com/repos/thoughtbot/factory_girl/contributors')
    # 看好,这里是 JSON.load 坑爹!!!
    response = JSON.load(Net::HTTP.get(uri))

    expect(response.first['login']).to eq 'joshuaclayton'
  end
end

file9.rb

$ rspec spec/features/external_request_spec.rb
.

Finished in 0.04713 seconds
1 example, 0 failures