Ruby on rails 运行Rspec时XPath不是模块（类型错误）

由于某些原因，我无法在rspec中运行我的测试。关于堆栈溢出的帖子说这可能是一个名称空间问题，但在我的代码库中（在我的视图中）并没有指出这一点。运行

rspec spec

后，出现以下错误

WARNING: Nokogiri was built against LibXML version 2.8.0, but has dynamically loaded 2.9.0
            /Users/garytsai/.rvm/gems/ruby-1.9.3-p545/gems/xpath-2.0.0/lib/xpath/dsl.rb:1:in `<top (required)>': XPath is not a module (TypeError)
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545/gems/xpath-2.0.0/lib/xpath.rb:3:in `require'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545/gems/xpath-2.0.0/lib/xpath.rb:3:in `<top (required)>'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545/gems/capybara-2.2.1/lib/capybara.rb:3:in `require'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545/gems/capybara-2.2.1/lib/capybara.rb:3:in `<top (required)>'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545@global/gems/bundler-1.6.0/lib/bundler/runtime.rb:76:in `require'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545@global/gems/bundler-1.6.0/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545@global/gems/bundler-1.6.0/lib/bundler/runtime.rb:72:in `each'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545@global/gems/bundler-1.6.0/lib/bundler/runtime.rb:72:in `block in require'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545@global/gems/bundler-1.6.0/lib/bundler/runtime.rb:61:in `each'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545@global/gems/bundler-1.6.0/lib/bundler/runtime.rb:61:in `require'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545@global/gems/bundler-1.6.0/lib/bundler.rb:132:in `require'
            from /Users/garytsai/Projects/reader-tool/config/application.rb:13:in `<top (required)>'
            from /Users/garytsai/Projects/reader-tool/config/environment.rb:2:in `require'
            from /Users/garytsai/Projects/reader-tool/config/environment.rb:2:in `<top (required)>'
            from /Users/garytsai/Projects/reader-tool/spec/spec_helper.rb:3:in `require'
            from /Users/garytsai/Projects/reader-tool/spec/spec_helper.rb:3:in `<top (required)>'
            from /Users/garytsai/Projects/reader-tool/spec/controllers/readers_controller_spec.rb:1:in `require'
            from /Users/garytsai/Projects/reader-tool/spec/controllers/readers_controller_spec.rb:1:in `<top (required)>'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545/gems/rspec-core-2.14.7/lib/rspec/core/configuration.rb:896:in `load'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545/gems/rspec-core-2.14.7/lib/rspec/core/configuration.rb:896:in `block in load_spec_files'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545/gems/rspec-core-2.14.7/lib/rspec/core/configuration.rb:896:in `each'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545/gems/rspec-core-2.14.7/lib/rspec/core/configuration.rb:896:in `load_spec_files'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545/gems/rspec-core-2.14.7/lib/rspec/core/command_line.rb:22:in `run'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545/gems/rspec-core-2.14.7/lib/rspec/core/runner.rb:80:in `run'
            from /Users/garytsai/.rvm/gems/ruby-1.9.3-p545/gems/rspec-core-2.14.7/lib/rspec/core/runner.rb:17:in `block in autorun'

---

你试过运行

bundle exec rspec spec

吗？@urigassi我刚试过，同样的错误消息弹出。请注意，我刚才让rspec运行过。当我安装gem或其他东西时，一定发生了一些变化。我安装了ActiveAdmin，但随后卸载了它。这是我能想象的最后一个大变化，它改变了一些东西。

    ruby "1.9.3"

    gem 'rails', '3.2.14'
    gem 'jquery-rails'
    gem 'simple_form'
    gem 'pg'
    gem 'thin'
    gem 'XMLCanonicalizer'
    gem 'humanize'

    group :development do
      gem 'better_errors'
      gem 'binding_of_caller'
      gem 'debugger'
      gem 'quiet_assets'
      gem 'sextant'
    end

    group :test do
      gem 'capybara'
      gem 'selenium-webdriver'
      gem 'shoulda-matchers'
      gem 'simplecov'
      gem 'database_cleaner'
    end

    group :development, :test do
      gem 'rspec-rails'
      gem "factory_girl_rails", "~> 4.0"
      gem 'faker'
      gem "rack_session_access"
      gem 'populator'
      gem 'dotenv'
    end

    group :assets do
      gem 'sass-rails',   '~> 3.2.3'
      gem 'coffee-rails', '~> 3.2.1'
      gem 'uglifier', '>= 1.0.3'
      gem 'twitter-bootstrap-rails'
      gem "less-rails"
      gem "therubyracer"
    end