title: rspec - uninitialized constant Rails (NameError) - a new case
body: <p>Off course I read this:</p>
  
  <p><a href="https://stackoverflow.com/questions/19692297/rspec-testing-throws-uninitialized-constant-rails-nameerror">rspec testing throws Uninitialized constant Rails (NameError)</a></p>
  
  <p>But I am sure that there is nothing wrong with my code.</p>
  
  <p>Just because of the operation system! (Thread?)</p>
  
  <p>Here is the error message when ran <code>rspec</code>:</p>
  
  <pre><code>/home/user/testapp/spec/spec_helper.rb:26:in `block in &lt;top (required)&gt;': uninitialized constant Rails (NameError)
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/lib/rspec/core.rb:98:in `configure'
      from /home/user/testapp/spec/spec_helper.rb:22:in `&lt;top (required)&gt;'
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/lib/rspec/core/configuration.rb:1394:in `block in requires='
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/lib/rspec/core/configuration.rb:1394:in `each'
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/lib/rspec/core/configuration.rb:1394:in `requires='
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/lib/rspec/core/configuration_options.rb:112:in `block in process_options_into'
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/lib/rspec/core/configuration_options.rb:111:in `each'
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/lib/rspec/core/configuration_options.rb:111:in `process_options_into'
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/lib/rspec/core/configuration_options.rb:21:in `configure'
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/lib/rspec/core/runner.rb:99:in `setup'
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/lib/rspec/core/runner.rb:86:in `run'
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/lib/rspec/core/runner.rb:71:in `run'
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/lib/rspec/core/runner.rb:45:in `invoke'
      from /home/user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rspec-core-3.5.4/exe/rspec:4:in `&lt;top (required)&gt;'
      from /home/user/.rbenv/versions/2.3.1/bin/rspec:23:in `load'
      from /home/user/.rbenv/versions/2.3.1/bin/rspec:23:in `&lt;main&gt;'
  </code></pre>
  
  <p>The L26 of the spec_helper file is:</p>
  
  <pre><code>Rails.application.env_config['action_dispatch.show_detailed_exceptions'] = false
  </code></pre>