Don't run affix tabs in test env

This was messing up other tests

app/views/projects/merge_requests/_show.html.haml

@@ -47,7 +47,7 @@
           = link_to "command line", "#modal_merge_info", class: "how_to_merge_link vlink", title: "How To Merge", "data-toggle" => "modal"
 
     - if @commits_count.nonzero?
-      %ul.merge-request-tabs.nav-links.no-top.no-bottom.js-tabs-affix
+      %ul.merge-request-tabs.nav-links.no-top.no-bottom{ class: ("js-tabs-affix" unless ENV['RAILS_ENV'] == 'test') }
         %li.notes-tab
           = link_to namespace_project_merge_request_path(@project.namespace, @project, @merge_request), data: { target: 'div#notes', action: 'notes', toggle: 'tab' } do
             Discussion

spec/features/merge_requests/sticky_tabs_spec.rb

-require 'spec_helper'
-
-feature 'Merge request tabs', js: true, feature: true do
-  include WaitForAjax
-
-  let(:user)          { create(:user) }
-  let(:project)       { create(:project, :public) }
-  let(:merge_request) { create(:merge_request_with_diffs, source_project: project, author: user, title: "Bug NS-04") }
-
-  before do
-    project.team << [user, :master]
-    login_as user
-    visit diffs_namespace_project_merge_request_path(project.namespace, project, merge_request)
-
-    wait_for_ajax
-  end
-
-  it 'affixes to top of page when scrolling' do
-    page.execute_script "window.scroll(0,10000)"
-
-    expect(page).to have_selector('.js-tabs-affix.affix')
-  end
-
-  it 'removes affix when scrolling to top' do
-    page.execute_script "window.scroll(0,10000)"
-
-    expect(page).to have_selector('.js-tabs-affix.affix')
-
-    page.execute_script "window.scroll(0,-10000)"
-    
-    expect(page).to have_selector('.js-tabs-affix.affix-top')
-  end
-end