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import { setHTMLFixture, resetHTMLFixture } from 'helpers/fixtures';
import findAndFollowLink from '~/lib/utils/navigation_utility';
import * as navigationUtils from '~/lib/utils/navigation_utility';
import { visitUrl } from '~/lib/utils/url_utility';
jest.mock('~/lib/utils/url_utility');
describe('findAndFollowLink', () => {
it('visits a link when the selector exists', () => {
const href = '/some/path';
setHTMLFixture(`<a class="my-shortcut" href="${href}">link</a>`);
findAndFollowLink('.my-shortcut');
expect(visitUrl).toHaveBeenCalledWith(href);
resetHTMLFixture();
});
it('does not throw an exception when the selector does not exist', () => {
// this should not throw an exception
findAndFollowLink('.this-selector-does-not-exist');
expect(visitUrl).not.toHaveBeenCalled();
});
});
describe('prefetchDocument', () => {
it('creates a prefetch link tag', () => {
const linkElement = document.createElement('link');
jest.spyOn(document, 'createElement').mockImplementation(() => linkElement);
jest.spyOn(document.head, 'appendChild');
navigationUtils.prefetchDocument('index.htm');
expect(document.head.appendChild).toHaveBeenCalledWith(linkElement);
expect(linkElement.href).toEqual('http://test.host/index.htm');
expect(linkElement.rel).toEqual('prefetch');
expect(linkElement.getAttribute('as')).toEqual('document');
});
});
describe('initPrefetchLinks', () => {
let newLink;
beforeEach(() => {
newLink = document.createElement('a');
newLink.href = 'index_prefetch.htm';
newLink.classList.add('js-test-prefetch-link');
document.body.appendChild(newLink);
});
it('adds to all links mouse out handlers when hovered', () => {
const mouseOverEvent = new Event('mouseover');
jest.spyOn(newLink, 'addEventListener');
navigationUtils.initPrefetchLinks('.js-test-prefetch-link');
newLink.dispatchEvent(mouseOverEvent);
expect(newLink.addEventListener).toHaveBeenCalled();
});
it('it is not fired when less then 100ms over link', () => {
const mouseOverEvent = new Event('mouseover');
const mouseOutEvent = new Event('mouseout');
jest.spyOn(newLink, 'addEventListener');
jest.spyOn(navigationUtils, 'prefetchDocument').mockImplementation(() => true);
navigationUtils.initPrefetchLinks('.js-test-prefetch-link');
newLink.dispatchEvent(mouseOverEvent);
newLink.dispatchEvent(mouseOutEvent);
expect(navigationUtils.prefetchDocument).not.toHaveBeenCalled();
});
describe('executes correctly when hovering long enough', () => {
const mouseOverEvent = new Event('mouseover');
beforeEach(() => {
jest.useFakeTimers();
jest.spyOn(global, 'setTimeout');
jest.spyOn(newLink, 'removeEventListener');
});
it('calls prefetchDocument which adds to document', () => {
jest.spyOn(document.head, 'appendChild');
navigationUtils.initPrefetchLinks('.js-test-prefetch-link');
newLink.dispatchEvent(mouseOverEvent);
jest.runAllTimers();
expect(setTimeout).toHaveBeenCalledWith(expect.any(Function), 100);
expect(document.head.appendChild).toHaveBeenCalled();
});
it('removes Event Listener when fired so only done once', () => {
navigationUtils.initPrefetchLinks('.js-test-prefetch-link');
newLink.dispatchEvent(mouseOverEvent);
jest.runAllTimers();
expect(newLink.removeEventListener).toHaveBeenCalledWith(
'mouseover',
expect.any(Function),
true,
);
});
});
});
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