Why does shallow Rendering not work as expected?

Use ().toEqual() instead of .to.have.length() as .to.have is not any function in jest expect library Visit here for more info

import React from "react";
import TestUser from "./testuser";
import { shallow } from "enzyme";

it("should render right", () => {
const component = shallow(<TestUser />);

expect(component.find('Card').length).toEqual(3);
});