Enzyme

Enzyme is a JavaScript Testing utility for React that makes it easier to assert, manipulate, and traverse your React Components' output.

Enzyme's API is meant to be intuitive and flexible by mimicking jQuery's API for DOM manipulation and traversal.

Enzyme is unopinionated regarding which test runner or assertion library you use, and should be compatible with all major test runners and assertion libraries out there. The documentation and examples for enzyme use mocha and chai, but you should be able to extrapolate to your framework of choice.

If you are interested in using enzyme with custom Chai.js assertions and convenience functions for testing your React components, you can consider using chai-enzyme.

If you are interested in using enzyme with custom Jasmine/Jest assertions and convenience functions for testing your React components, you can consider using jasmine-enzyme.

Using Enzyme with Mocha

Using Enzyme with Karma

Using Enzyme with Browserify

Using Enzyme with WebPack

Using Enzyme with JSDOM

Using Enzyme with React Native

Using Enzyme with Jest

Using Enzyme with Lab

Installation

To get started with enzyme, you can simply install it with npm:

npm i --save-dev enzyme

Enzyme is currently compatible with React 15.x, React 0.14.x and React 0.13.x. In order to achieve this compatibility, some dependencies cannot be explicitly listed in our package.json.

If you are using React 0.14 or React 15.x, in addition to enzyme, you will have to ensure that you also have the following npm modules installed if they were not already:

npm i --save-dev react-addons-test-utils
npm i --save-dev react-dom

Basic Usage

Shallow Rendering

import React from 'react';
import { shallow } from 'enzyme';
import sinon from 'sinon';

describe('<MyComponent />', () => {

  it('renders three <Foo /> components', () => {
    const wrapper = shallow(<MyComponent />);
    expect(wrapper.find(Foo)).to.have.length(3);
  });

  it('renders an `.icon-star`', () => {
    const wrapper = shallow(<MyComponent />);
    expect(wrapper.find('.icon-star')).to.have.length(1);
  });

  it('renders children when passed in', () => {
    const wrapper = shallow(
      <MyComponent>
        <div className="unique" />
      </MyComponent>
    );
    expect(wrapper.contains(<div className="unique" />)).to.equal(true);
  });

  it('simulates click events', () => {
    const onButtonClick = sinon.spy();
    const wrapper = shallow(
      <Foo onButtonClick={onButtonClick} />
    );
    wrapper.find('button').simulate('click');
    expect(onButtonClick.calledOnce).to.equal(true);
  });

});

Read the full API Documentation

Full DOM Rendering

import React from 'react';
import sinon from 'sinon';
import { mount } from 'enzyme';

describe('<Foo />', () => {

  it('allows us to set props', () => {
    const wrapper = mount(<Foo bar="baz" />);
    expect(wrapper.props().bar).to.equal("baz");
    wrapper.setProps({ bar: "foo" });
    expect(wrapper.props().bar).to.equal("foo");
  });

  it('simulates click events', () => {
    const onButtonClick = sinon.spy();
    const wrapper = mount(
      <Foo onButtonClick={onButtonClick} />
    );
    wrapper.find('button').simulate('click');
    expect(onButtonClick.calledOnce).to.equal(true);
  });

  it('calls componentDidMount', () => {
    sinon.spy(Foo.prototype, 'componentDidMount');
    const wrapper = mount(<Foo />);
    expect(Foo.prototype.componentDidMount.calledOnce).to.be.true;
    Foo.prototype.componentDidMount.restore();
  });

});

Read the full API Documentation

Static Rendered Markup

import React from 'react';
import { render } from 'enzyme';

describe('<Foo />', () => {

  it('renders three `.foo-bar`s', () => {
    const wrapper = render(<Foo />);
    expect(wrapper.find('.foo-bar').length).to.equal(3);
  });

  it('renders the title', () => {
    const wrapper = render(<Foo title="unique" />);
    expect(wrapper.text()).to.contain("unique");
  });

});