I found a red Jenkins build with no test failures, the problem might not be immediately clear.  In the logs I find this, which seems to be the cause of the build failure: 

Feature: Loading pages

  Background:                                          # features/page_loading.feature:4
    Given the page "Selenium page loading test" exists # features/step_definitions/create_page_api_steps.rb:42

  Scenario: Page loads without ajax in stable                         # features/page_loading.feature:7
    Given I visit a protected page                                    # features/step_definitions/create_page_api_steps.rb:86
      Undefined step: "The "Selenium protected test 2" page is protected." (Cucumber::Undefined)
      /scratch/jenkins/addons/ruby/ruby-2.1.1-x86_64/lib/ruby/gems/2.1.0/gems/cucumber-1.3.14/lib/cucumber/runtime/support_code.rb:145:in `step_match_without_cache'


https://wmf.ci.cloudbees.com/job/MobileFrontend-en.m.wikipedia.beta.wmflabs.org-linux-firefox/601/console