import { renderHook } from '@testing-library/react-hooks'; import useFavicon from '../src/useFavicon'; afterEach(() => { const favicon = document.querySelector("link[rel*='icon']"); if (favicon) { favicon.remove(); } }); describe('useFavicon', () => { it('should be defined', () => { expect(useFavicon).toBeDefined(); }); it('should create a HTMLLinkElement', () => { const faviconBeforeHook = document.querySelector("link[rel*='icon']"); expect(faviconBeforeHook).toBe(null); renderHook(() => useFavicon('My-favicon')); const faviconAfterHook = document.querySelector("link[rel*='icon']"); expect(faviconAfterHook).toBeInstanceOf(HTMLLinkElement); }); it('should set the elements type to "image/x-icon"', () => { renderHook(() => useFavicon('My-favicon')); const favicon = document.querySelector("link[rel*='icon']") as HTMLLinkElement; expect(favicon.type).toBe('image/x-icon'); }); it('should set the elements rel to "shortcut icon"', () => { renderHook(() => useFavicon('My-favicon')); const favicon = document.querySelector("link[rel*='icon']") as HTMLLinkElement; expect(favicon.rel).toBe('shortcut icon'); }); it('should set the elements href to the provided string', () => { renderHook(() => useFavicon('https://github.com/streamich/react-use')); const favicon = document.querySelector("link[rel*='icon']") as HTMLLinkElement; expect(favicon.href).toBe('https://github.com/streamich/react-use'); }); it('should update an existing favicon', () => { const hook = renderHook((props) => useFavicon(props), { initialProps: 'https://github.com/streamich/react-use', }); const favicon = document.querySelector("link[rel*='icon']") as HTMLLinkElement; expect(favicon.href).toBe('https://github.com/streamich/react-use'); hook.rerender('https://en.wikipedia.org/wiki/Favicon'); expect(favicon.href).toBe('https://en.wikipedia.org/wiki/Favicon'); }); });