Merge branch 'register-tab' into 'master'

Only show register tab if signup enabled.

## What does this MR do?

Fixes a regression where the register tab is activated, even if sign-up enabled is not activated in application_settings.

## Screenshots (if relevant)

When signup is disabled: 

![Screen_Shot_2016-10-22_at_8.56.23_PM](/uploads/bd0fa5f27114779c0d290a8151c1c253/Screen_Shot_2016-10-22_at_8.56.23_PM.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) entry added
- [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/23654

See merge request !7058

CHANGELOG.md

@@ -23,6 +23,7 @@ Please view this file on the master branch, on stable branches it's out of date.
   - Fix 404 for group pages when GitLab setup uses relative url
   - Simpler arguments passed to named_route on toggle_award_url helper method 
   - Better handle when no users were selected for adding to group or project. (Linus Thiel)
+  - Only show register tab if signup enabled.
 
 ## 8.13.0 (2016-10-22)
   - Removes extra line for empty issue description. (!7045)

app/views/devise/shared/_tabs_normal.html.haml

 %ul.nav-links.new-session-tabs.nav-tabs{ role: 'tablist'}
   %li.active{ role: 'presentation' }
     %a{ href: '#login-pane', data: { toggle: 'tab' }, role: 'tab'} Sign in
+  - if signin_enabled? && signup_enabled?
     %li{ role: 'presentation'}
       %a{ href: '#register-pane', data: { toggle: 'tab' }, role: 'tab'} Register

spec/features/login_spec.rb

@@ -215,4 +215,69 @@ feature 'Login', feature: true do
       end
     end
   end
+
+  describe 'UI tabs and panes' do
+    context 'when no defaults are changed' do
+      it 'correctly renders tabs and panes' do
+        ensure_tab_pane_correctness
+      end
+    end
+
+    context 'when signup is disabled' do
+      before do
+        stub_application_setting(signup_enabled: false)
+      end
+
+      it 'correctly renders tabs and panes' do
+        ensure_tab_pane_correctness
+      end
+    end
+
+    context 'when ldap is enabled' do
+      before do
+        visit new_user_session_path
+        allow(page).to receive(:form_based_providers).and_return([:ldapmain])
+        allow(page).to receive(:ldap_enabled).and_return(true)
+      end
+
+      it 'correctly renders tabs and panes' do
+        ensure_tab_pane_correctness(false)
+      end
+    end
+
+    context 'when crowd is enabled' do
+      before do
+        visit new_user_session_path
+        allow(page).to receive(:form_based_providers).and_return([:crowd])
+        allow(page).to receive(:crowd_enabled?).and_return(true)
+      end
+
+      it 'correctly renders tabs and panes' do
+        ensure_tab_pane_correctness(false)
+      end
+    end
+
+    def ensure_tab_pane_correctness(visit_path = true)
+      if visit_path
+        visit new_user_session_path
+      end
+
+      ensure_tab_pane_counts
+      ensure_one_active_tab
+      ensure_one_active_pane
+    end
+
+    def ensure_tab_pane_counts
+      tabs_count = page.all('[role="tab"]').size
+      expect(page).to have_selector('[role="tabpanel"]', count: tabs_count)
+    end
+
+    def ensure_one_active_tab
+      expect(page).to have_selector('.nav-tabs > li.active', count: 1)
+    end
+
+    def ensure_one_active_pane
+      expect(page).to have_selector('.tab-pane.active', count: 1)
+    end
+  end
 end