Add latest changes from gitlab-org/gitlab@master

1 files changed, 55 insertions, 1 deletions

diff --git a/spec/frontend/diffs/utils/merge_request_spec.js b/spec/frontend/diffs/utils/merge_request_spec.js
index c070e8c004d..21599a3be45 100644
--- a/spec/frontend/diffs/utils/merge_request_spec.js
+++ b/spec/frontend/diffs/utils/merge_request_spec.js
@@ -1,4 +1,8 @@
-import { getDerivedMergeRequestInformation } from '~/diffs/utils/merge_request';
+import {
+  updateChangesTabCount,
+  getDerivedMergeRequestInformation,
+} from '~/diffs/utils/merge_request';
+import { ZERO_CHANGES_ALT_DISPLAY } from '~/diffs/constants';
 import { diffMetadata } from '../mock_data/diff_metadata';
 
 describe('Merge Request utilities', () => {
@@ -24,6 +28,56 @@ describe('Merge Request utilities', () => {
     ...noVersion,
   };
 
+  describe('updateChangesTabCount', () => {
+    let dummyTab;
+    let badge;
+
+    beforeEach(() => {
+      dummyTab = document.createElement('div');
+      dummyTab.classList.add('js-diffs-tab');
+      dummyTab.insertAdjacentHTML('afterbegin', '<span class="gl-badge">ERROR</span>');
+      badge = dummyTab.querySelector('.gl-badge');
+    });
+
+    afterEach(() => {
+      dummyTab.remove();
+      dummyTab = null;
+      badge = null;
+    });
+
+    it('uses the alt hyphen display when the new changes are falsey', () => {
+      updateChangesTabCount({ count: 0, badge });
+
+      expect(dummyTab.textContent).toBe(ZERO_CHANGES_ALT_DISPLAY);
+
+      updateChangesTabCount({ badge });
+
+      expect(dummyTab.textContent).toBe(ZERO_CHANGES_ALT_DISPLAY);
+
+      updateChangesTabCount({ count: false, badge });
+
+      expect(dummyTab.textContent).toBe(ZERO_CHANGES_ALT_DISPLAY);
+    });
+
+    it('uses the actual value for display when the value is truthy', () => {
+      updateChangesTabCount({ count: 42, badge });
+
+      expect(dummyTab.textContent).toBe('42');
+
+      updateChangesTabCount({ count: '999+', badge });
+
+      expect(dummyTab.textContent).toBe('999+');
+    });
+
+    it('selects the proper element to modify by default', () => {
+      document.body.insertAdjacentElement('afterbegin', dummyTab);
+
+      updateChangesTabCount({ count: 42 });
+
+      expect(dummyTab.textContent).toBe('42');
+    });
+  });
+
   describe('getDerivedMergeRequestInformation', () => {
     let endpoint = `${diffMetadata.latest_version_path}.json?searchParam=irrelevant`;