global['CSS'] = null; const mock = () => { let storage = {}; return { getItem: key => (key in storage ? storage[key] : null), setItem: (key, value) => (storage[key] = value || ''), removeItem: key => delete storage[key], clear: () => (storage = {}) }; }; Object.defineProperty(window, 'localStorage', { value: mock() }); Object.defineProperty(window, 'sessionStorage', { value: mock() }); Object.defineProperty(document, 'doctype', { value: '' }); Object.defineProperty(window, 'getComputedStyle', { value: () => { return { display: 'none', appearance: ['-webkit-appearance'] }; } }); Object.defineProperty(document.body.style, 'transform', { value: () => { return { enumerable: true, configurable: true }; } });