rspec failing feature when a helper has a class inside the module

helper_with_class.feature

  Scenario: failing test when a helper has a class inside a module
    Given a file named "spec/helpers/with_class_helper_spec.rb" with:
      """
      require "spec_helper"

      describe WithClassHelper do
        describe FooClass  do
          it 'works' do
            helper.works.should be_true 
          end
        end
      end
      """
    And a file named "app/helpers/with_class_helper.rb" with:
      """
      module WithClassHelper
        class FooClass
          def works
            true
          end
        end
      end
      """
    When I run "rspec spec/helpers/with_class_helper_spec.rb"
    Then the output should contain "uninitialized constant FooClass"