我正在尝试对一些非常简单的 Ruby 进行测试。我的 linux 机器上安装了 ruby 和 rails。我也安装了 rspec。我的宝石清单是：
LOCAL GEMS
actionmailer (3.2.8)
actionpack (3.2.8)
activemodel (3.2.8)
activerecord (3.2.8)
activeresource (3.2.8)
activesupport (3.2.8)
arel (3.0.2)
builder (3.0.0)
bundler (1.2.0, 1.1.5)
diff-lcs (1.1.3)
erubis (2.7.0)
hike (1.2.1)
i18n (0.6.1, 0.6.0)
journey (1.0.4)
json (1.7.5)
mail (2.4.4)
mime-types (1.19)
multi_json (1.3.6)
polyglot (0.3.3)
rack (1.4.1)
rack-cache (1.2)
rack-ssl (1.3.2)
rack-test (0.6.1)
rails (3.2.8)
railties (3.2.8)
rake (0.9.2.2)
rdoc (3.12)
rspec (2.11.0)
rspec-core (2.11.1)
rspec-expectations (2.11.2)
rspec-mocks (2.11.2)
rubygems-bundler (1.0.7)
rvm (1.11.3.5)
sprockets (2.4.5, 2.1.3)
thor (0.16.0)
tilt (1.3.3)
treetop (1.4.10)
tzinfo (0.3.33)
但是当我跑步时
rspec my_test_file.rb
我收到以下错误：
/usr/lib/ruby/vendor_ruby/rspec/core/mocking/with_rspec.rb:1:in `require': no such file to load -- rspec/mocks (LoadError)
from /usr/lib/ruby/vendor_ruby/rspec/core/mocking/with_rspec.rb:1
from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:116:in `require'
from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:116:in `mock_framework'
from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:376:in `configure_mock_framework'
from /usr/lib/ruby/vendor_ruby/rspec/core/command_line.rb:19:in `run'
from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:55:in `run_in_process'
from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:46:in `run'
from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:10:in `autorun'
from /usr/bin/rspec:4
这似乎特定于 rspec/mocks（与 SE 上发布的其他“没有要加载的文件”红宝石错误不同）。那么我错过了什么？