Merge branch '15081-wrong-login-tab-ldap-frontend' into 'master'

Fixed Wrong Tab Selected When Loggin Fails And Multiple Login Tabs Exists

## What does this MR do?
Fixes issue: 15081 Wrong Tab Selected When Loggin Fails And Multiple Login Tabs Exists
This is done by saving into a cookie when the active tab changes and by always selecting that tab when the page is loaded.
## Are there points in the code the reviewer needs to double check?
No
## Why was this MR needed?
In order to fix the issue: 15081
## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] 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?


Closes #15081

See merge request !7314

2 files changed, 58 insertions, 0 deletions

diff --git a/spec/javascripts/fixtures/signin_tabs.html.haml b/spec/javascripts/fixtures/signin_tabs.html.haml
new file mode 100644
index 00000000000..12b8d423cbe
--- /dev/null
+++ b/spec/javascripts/fixtures/signin_tabs.html.haml
@@ -0,0 +1,5 @@
+%ul.nav-tabs
+  %li
+    %a.active{ id: 'standard', href: '#standard'} Standard
+  %li
+    %a{ id: 'ldap', href: '#ldap'} Ldap
diff --git a/spec/javascripts/signin_tabs_memoizer_spec.js.es6 b/spec/javascripts/signin_tabs_memoizer_spec.js.es6
new file mode 100644
index 00000000000..9a9fb22255b
--- /dev/null
+++ b/spec/javascripts/signin_tabs_memoizer_spec.js.es6
@@ -0,0 +1,53 @@
+/*= require signin_tabs_memoizer */
+
+((global) => {
+  describe('SigninTabsMemoizer', () => {
+    const fixtureTemplate = 'signin_tabs.html';
+    const tabSelector = 'ul.nav-tabs';
+    const currentTabKey = 'current_signin_tab';
+    let memo;
+
+    function createMemoizer() {
+      memo = new global.ActiveTabMemoizer({
+        currentTabKey,
+        tabSelector,
+      });
+      return memo;
+    }
+
+    fixture.preload(fixtureTemplate);
+
+    beforeEach(() => {
+      fixture.load(fixtureTemplate);
+    });
+
+    it('does nothing if no tab was previously selected', () => {
+      createMemoizer();
+
+      expect(document.querySelector('li a.active').getAttribute('id')).toEqual('standard');
+    });
+
+    it('shows last selected tab on boot', () => {
+      createMemoizer().saveData('#ldap');
+      const fakeTab = {
+        click: () => {},
+      };
+      spyOn(document, 'querySelector').and.returnValue(fakeTab);
+      spyOn(fakeTab, 'click');
+
+      memo.bootstrap();
+
+      // verify that triggers click on the last selected tab
+      expect(document.querySelector).toHaveBeenCalledWith(`${tabSelector} a[href="#ldap"]`);
+      expect(fakeTab.click).toHaveBeenCalled();
+    });
+
+    it('saves last selected tab on change', () => {
+      createMemoizer();
+
+      document.getElementById('standard').click();
+
+      expect(memo.readData()).toEqual('#standard');
+    });
+  });
+})(window);