“ Bundle Exec Rspec”的Ruby on Rails BDD错误无法加载此类文件-ffi（LoadError）

Question

我正在使用Michael Hartl的Ruby on Rails教程来学习Rails。 我在第3.2.2节（测试驱动开发）中，当我运行以下命令来运行rspec测试时：

$ bundle exec rspec spec / requests / static_pages_spec.rb

我收到以下错误：

  c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/childprocess-0.5.1/lib/childprocess/windows.rb:1:in `require': cannot load such file -- ffi (LoadError) from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/childprocess-0.5.1/lib/childprocess/windows.rb:1:in `<top (required)>' from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/childprocess-0.5.1/lib/childprocess.rb:176:in `require'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/childprocess-0.5.1/lib/childprocess.rb:176:in `<top (required)>'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/selenium-webdriver-2.35.1/lib/selenium/webdriver.rb:1:in `require'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/selenium-webdriver-2.35.1/lib/selenium/webdriver.rb:1:in `<top (required)>'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/selenium-webdriver-2.35.1/lib/selenium-webdriver.rb:1:in `require'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/selenium-webdriver-2.35.1/lib/selenium-webdriver.rb:1:in `<top (required)>'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `require'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `each'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `block in require'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `each'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `require'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/bundler-1.3.5/lib/bundler.rb:132:in `require'
from d:/source/training/ruby/railstutorial/sample_app/config/application.rb:12:in `<top (required)>'
from d:/source/training/ruby/railstutorial/sample_app/config/environment.rb:2:in `require'
from d:/source/training/ruby/railstutorial/sample_app/config/environment.rb:2:in `<top (required)>'
from d:/source/training/ruby/railstutorial/sample_app/spec/spec_helper.rb:3:in `require'
from d:/source/training/ruby/railstutorial/sample_app/spec/spec_helper.rb:3:in `<top (required)>'
from d:/source/training/ruby/railstutorial/sample_app/spec/requests/static_pages_spec.rb:1:in `require'
from d:/source/training/ruby/railstutorial/sample_app/spec/requests/static_pages_spec.rb:1:in `<top (required)>'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/rspec-core-2.13.1/lib/rspec/core/configuration.rb:819:in `load'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/rspec-core-2.13.1/lib/rspec/core/configuration.rb:819:in `block in load_spec_files'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/rspec-core-2.13.1/lib/rspec/core/configuration.rb:819:in `each'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/rspec-core-2.13.1/lib/rspec/core/configuration.rb:819:in `load_spec_files'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/rspec-core-2.13.1/lib/rspec/core/command_line.rb:22:in `run'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/rspec-core-2.13.1/lib/rspec/core/runner.rb:80:in `run'
from c:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/rspec-core-2.13.1/lib/rspec/core/runner.rb:17:in `block in autorun'

这是我的Gemfile：

     source 'https://rubygems.org'
     ruby '2.0.0'

    gem 'rails', '4.0.3'

    group :development, :test do
     gem 'sqlite3', '1.3.8'
     gem 'rspec-rails', '2.13.1'
   end

   group :test do
    gem  'selenium-webdriver', '~> 2.35.1'
    gem 'capybara', '2.1.0'
  end

  gem 'sass-rails', '4.0.1'
  gem 'uglifier', '2.1.1'
  gem 'coffee-rails', '4.0.1'
  gem 'jquery-rails', '3.0.4'
  gem 'turbolinks', '1.1.1'
  gem 'jbuilder', '1.0.2'

  group :doc do
   gem 'sdoc', '0.3.20', require: false
  end

  group :production do
   gem 'pg', '0.15.1'
   gem 'rails_12factor', '0.0.2'
  end

这是我的static_pages_spec.rb

  require 'spec_helper'

 describe "Static pages" do

 describe "Home page" do

  it "should have the content 'Sample App'" do
   visit 'static_pages/home'
   expect(page).to have_content('Sample App')
  end
 end
end

当我评论这一行

  #require 'spec_helper'

然后出现红色失败测试，​​但有一些错误，表明它无法识别某些功能，例如访问。 我尝试安装无法显示错误消息的ffi，但仍然出现此错误。

操作系统 ： Windows 7 x64 ，有什么帮助吗？

谢谢

Answer 1

根据此https://github.com/ffi/ffi/issues/176，您应将其安装为

gem install ffi --platform=ruby

Answer 2

每次找到它时，都必须在gemfile.lock中将del X86替换为X64。 例如，您必须用此ffi（1.9.3-x64-mingw32）替换此ffi（1.9.3-x86 -mingw32）。

进行这些更改后，保存gemfile.lock并捆绑安装

Answer 3

如果以上解决方案均无效，请尝试在gem文件中显式声明gem。 它对我有用。

gem 'ffi'

注意：您可能仍然需要安装MikeZ提到的gem

gem install ffi --platform=ruby