```ruby
require File.expand_path('../../../spec_helper', __FILE__)
require File.expand_path('../fixtures/common', __FILE__)
require File.expand_path('../shared/exist', __FILE__)

describe "Dir.exist?" do
  before :all do
    DirSpecs.create_mock_dirs
  end

  after :all do
    DirSpecs.delete_mock_dirs
  end

  it_behaves_like(:dir_exist, :exists?)
end
```

Fix name in the describe block of Dir.exists?.
user
```ruby
require File.expand_path('../../../spec_helper', __FILE__)
require File.expand_path('../fixtures/common', __FILE__)
require File.expand_path('../shared/exist', __FILE__)

describe "Dir.exists?" do
  before :all do
    DirSpecs.create_mock_dirs
  end

  after :all do
    DirSpecs.delete_mock_dirs
  end

  it_behaves_like(:dir_exist, :exists?)
end
```
assistant