1 files changed, 25 insertions, 0 deletions
diff --git a/spec/frontend/diffs/components/diff_view_spec.js b/spec/frontend/diffs/components/diff_view_spec.js
index cfc80e61b30..8778683c135 100644
--- a/spec/frontend/diffs/components/diff_view_spec.js
+++ b/spec/frontend/diffs/components/diff_view_spec.js
@@ -1,10 +1,14 @@
 import { shallowMount } from '@vue/test-utils';
 import Vue, { nextTick } from 'vue';
 import Vuex from 'vuex';
+import { throttle } from 'lodash';
 import DiffView from '~/diffs/components/diff_view.vue';
 import DiffLine from '~/diffs/components/diff_line.vue';
 import { diffCodeQuality } from '../mock_data/diff_code_quality';
 
+jest.mock('lodash/throttle', () => jest.fn((fn) => fn));
+const lodash = jest.requireActual('lodash');
+
 describe('DiffView', () => {
   const DiffExpansionCell = { template: `<div/>` };
   const DiffRow = { template: `<div/>` };
@@ -51,6 +55,14 @@ describe('DiffView', () => {
     return shallowMount(DiffView, { propsData, store, stubs });
   };
 
+  beforeEach(() => {
+    throttle.mockImplementation(lodash.throttle);
+  });
+
+  afterEach(() => {
+    throttle.mockReset();
+  });
+
   it('does not render a diff-line component when there is no finding', () => {
     const wrapper = createWrapper();
     expect(wrapper.findComponent(DiffLine).exists()).toBe(false);
@@ -138,5 +150,18 @@ describe('DiffView', () => {
       expect(wrapper.vm.idState.dragStart).toBeNull();
       expect(showCommentForm).toHaveBeenCalled();
     });
+
+    it('throttles multiple calls to enterdragging', () => {
+      const wrapper = createWrapper({ diffLines: [{}] });
+      const diffRow = getDiffRow(wrapper);
+
+      diffRow.$emit('startdragging', { line: { chunk: 1, index: 1 } });
+      diffRow.$emit('enterdragging', { chunk: 1, index: 2 });
+      diffRow.$emit('enterdragging', { chunk: 1, index: 2 });
+
+      jest.runOnlyPendingTimers();
+
+      expect(setSelectedCommentPosition).toHaveBeenCalledTimes(1);
+    });
   });
 });