title: trouble setting up cucumber to test without actually changing the file system
body: <p>I have been struggling for a while with this problem. I'm trying to test a ruby CLI that uses a lot of <code>fileutils</code> operations like making directories and copying files, etc. But when I'm writing tests, I need some way to test the functionality without touching and changing the actual filesystem. I am trying to use the <code>fakefs</code> gem but I am running into a error right away</p>
  
  <pre><code>When I successfully run `dotfiles init`                           # aruba-0.5.3/lib/aruba/cucumber.rb:71
        No such file or directory - No such file or directory - /tmp/aruba-out20130817-15800-ke8nou (Errno::ENOENT)
        /Users/Brian/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/tempfile.rb:146:in `open'
        /Users/Brian/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/tempfile.rb:146:in `block in initialize'
        /Users/Brian/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/tmpdir.rb:142:in `create'
        /Users/Brian/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/tempfile.rb:136:in `initialize'
        features/dotfiles_repository.feature:8:in `When I successfully run `dotfiles init`'
  </code></pre>
  
  <p>So its not finding <code>/tmp/aruba</code> which is where cucumber aruba does all of its file operations according to the <a href="https://github.com/cucumber/aruba" rel="nofollow">readme</a>.
  The tests run fine without <code>fakefs</code>, so I'm assuming its something with the setup.</p>
  
  <p>Here is my <code>features/support/env.rb</code> file</p>
  
  <pre><code>require 'aruba/cucumber'
  require 'fakefs/safe'
  
  Before do
    FakeFS.activate!
  end
  
  After do
    FakeFS::FileSystem.clear
    FakeFS.deactivate!
  end
  </code></pre>
  
  <p>Does anyone have any idea what I may be doing wrong? Any help is appreciated. Even if its an idea that doesn't use fakefs, I would like to hear it. Thanks</p>