Add latest changes from gitlab-org/gitlab@master

1 files changed, 115 insertions, 0 deletions

diff --git a/spec/frontend/lib/utils/dom_utils_spec.js b/spec/frontend/lib/utils/dom_utils_spec.js
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index 00000000000..10b4a10a8ff
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+++ b/spec/frontend/lib/utils/dom_utils_spec.js
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+import { addClassIfElementExists, canScrollUp, canScrollDown } from '~/lib/utils/dom_utils';
+
+const TEST_MARGIN = 5;
+
+describe('DOM Utils', () => {
+  describe('addClassIfElementExists', () => {
+    const className = 'biology';
+    const fixture = `
+      <div class="parent">
+        <div class="child"></div>
+      </div>
+    `;
+
+    let parentElement;
+
+    beforeEach(() => {
+      setFixtures(fixture);
+      parentElement = document.querySelector('.parent');
+    });
+
+    it('adds class if element exists', () => {
+      const childElement = parentElement.querySelector('.child');
+
+      expect(childElement).not.toBe(null);
+
+      addClassIfElementExists(childElement, className);
+
+      expect(childElement.classList).toContainEqual(className);
+    });
+
+    it('does not throw if element does not exist', () => {
+      const childElement = parentElement.querySelector('.other-child');
+
+      expect(childElement).toBe(null);
+
+      addClassIfElementExists(childElement, className);
+    });
+  });
+
+  describe('canScrollUp', () => {
+    [1, 100].forEach(scrollTop => {
+      it(`is true if scrollTop is > 0 (${scrollTop})`, () => {
+        expect(
+          canScrollUp({
+            scrollTop,
+          }),
+        ).toBe(true);
+      });
+    });
+
+    [0, -10].forEach(scrollTop => {
+      it(`is false if scrollTop is <= 0 (${scrollTop})`, () => {
+        expect(
+          canScrollUp({
+            scrollTop,
+          }),
+        ).toBe(false);
+      });
+    });
+
+    it('is true if scrollTop is > margin', () => {
+      expect(
+        canScrollUp(
+          {
+            scrollTop: TEST_MARGIN + 1,
+          },
+          TEST_MARGIN,
+        ),
+      ).toBe(true);
+    });
+
+    it('is false if scrollTop is <= margin', () => {
+      expect(
+        canScrollUp(
+          {
+            scrollTop: TEST_MARGIN,
+          },
+          TEST_MARGIN,
+        ),
+      ).toBe(false);
+    });
+  });
+
+  describe('canScrollDown', () => {
+    let element;
+
+    beforeEach(() => {
+      element = {
+        scrollTop: 7,
+        offsetHeight: 22,
+        scrollHeight: 30,
+      };
+    });
+
+    it('is true if element can be scrolled down', () => {
+      expect(canScrollDown(element)).toBe(true);
+    });
+
+    it('is false if element cannot be scrolled down', () => {
+      element.scrollHeight -= 1;
+
+      expect(canScrollDown(element)).toBe(false);
+    });
+
+    it('is true if element can be scrolled down, with margin given', () => {
+      element.scrollHeight += TEST_MARGIN;
+
+      expect(canScrollDown(element, TEST_MARGIN)).toBe(true);
+    });
+
+    it('is false if element cannot be scrolled down, with margin given', () => {
+      expect(canScrollDown(element, TEST_MARGIN)).toBe(false);
+    });
+  });
+});