1 files changed, 39 insertions, 0 deletions
diff --git a/spec/frontend/layout_nav_spec.js b/spec/frontend/layout_nav_spec.js
new file mode 100644
index 00000000000..30f4f7fcac1
--- /dev/null
+++ b/spec/frontend/layout_nav_spec.js
@@ -0,0 +1,39 @@
+import { initScrollingTabs } from '~/layout_nav';
+import { setHTMLFixture } from './__helpers__/fixtures';
+
+describe('initScrollingTabs', () => {
+  const htmlFixture = `
+    <button type='button' class='fade-left'></button>
+    <button type='button' class='fade-right'></button>
+    <div class='scrolling-tabs'></div>
+  `;
+  const findTabs = () => document.querySelector('.scrolling-tabs');
+  const findScrollLeftButton = () => document.querySelector('button.fade-left');
+  const findScrollRightButton = () => document.querySelector('button.fade-right');
+
+  beforeEach(() => {
+    setHTMLFixture(htmlFixture);
+  });
+
+  it('scrolls left when clicking on the left button', () => {
+    initScrollingTabs();
+    const tabs = findTabs();
+    tabs.scrollBy = jest.fn();
+    const fadeLeft = findScrollLeftButton();
+
+    fadeLeft.click();
+
+    expect(tabs.scrollBy).toHaveBeenCalledWith({ left: -200, behavior: 'smooth' });
+  });
+
+  it('scrolls right when clicking on the right button', () => {
+    initScrollingTabs();
+    const tabs = findTabs();
+    tabs.scrollBy = jest.fn();
+    const fadeRight = findScrollRightButton();
+
+    fadeRight.click();
+
+    expect(tabs.scrollBy).toHaveBeenCalledWith({ left: 200, behavior: 'smooth' });
+  });
+});