enzyme README

The project's README from github.com/enzymejs/enzyme. As one markdown file: README.md.

Enzyme

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Enzyme is a JavaScript Testing utility for React that makes it easier to test your React Components' output. You can also manipulate, traverse, and in some ways simulate runtime given the output.

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

Upgrading from Enzyme 2.x or React < 16

Are you here to check whether or not Enzyme is compatible with React 16? Are you currently using Enzyme 2.x? Great! Check out our migration guide for help moving on to Enzyme v3 where React 16 is supported.

Installation

To get started with enzyme, you can simply install it via npm. You will need to install enzyme along with an Adapter corresponding to the version of react (or other UI Component library) you are using. For instance, if you are using enzyme with React 16, you can run:

npm i --save-dev enzyme enzyme-adapter-react-16

Each adapter may have additional peer dependencies which you will need to install as well. For instance, enzyme-adapter-react-16 has peer dependencies on react and react-dom.

At the moment, Enzyme has adapters that provide compatibility with React 16.x, React 15.x, React 0.14.x and React 0.13.x.

The following adapters are officially provided by enzyme, and have the following compatibility with React:

Enzyme Adapter Package React semver compatibility
enzyme-adapter-react-16 ^16.4.0-0
enzyme-adapter-react-16.3 ~16.3.0-0
enzyme-adapter-react-16.2 ~16.2
enzyme-adapter-react-16.1 ~16.0.0-0 || ~16.1
enzyme-adapter-react-15 ^15.5.0
enzyme-adapter-react-15.4 15.0.0-0 - 15.4.x
enzyme-adapter-react-14 ^0.14.0
enzyme-adapter-react-13 ^0.13.0

Finally, you need to configure enzyme to use the adapter you want it to use. To do this, you can use the top level configure(...) API.

import Enzyme from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';

Enzyme.configure({ adapter: new Adapter() });

3rd Party Adapters

It is possible for the community to create additional (non-official) adapters that will make enzyme work with other libraries. If you have made one and it's not included in the list below, feel free to make a PR to this README and add a link to it! The known 3rd party adapters are:

Adapter Package For Library Status
enzyme-adapter-preact-pure preact (stable)
enzyme-adapter-inferno inferno (work in progress)

Running Enzyme Tests

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 assertions and convenience functions for testing your React components, you can consider using:

Using Enzyme with Mocha

Using Enzyme with Karma

Using Enzyme with Browserify

Using Enzyme with SystemJS

Using Enzyme with Webpack

Using Enzyme with JSDOM

Using Enzyme with React Native

Using Enzyme with Jest

Using Enzyme with Lab

Using Enzyme with Tape and AVA

Basic Usage

Shallow Rendering

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

import MyComponent from './MyComponent';
import Foo from './Foo';

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

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

Read the full API Documentation

Full DOM Rendering

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

import Foo from './Foo';

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).to.have.property('callCount', 1);
  });

  it('calls componentDidMount', () => {
    sinon.spy(Foo.prototype, 'componentDidMount');
    const wrapper = mount(<Foo />);
    expect(Foo.prototype.componentDidMount).to.have.property('callCount', 1);
    Foo.prototype.componentDidMount.restore();
  });
});

Read the full API Documentation

Static Rendered Markup

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

import Foo from './Foo';

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

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

Read the full API Documentation

React Hooks support

Enzyme supports react hooks with some limitations in .shallow() due to upstream issues in React's shallow renderer:

ReactTestUtils.act() wrap

If you're using React 16.8+ and .mount(), Enzyme will wrap apis including .simulate(), .setProps(), .setContext(), .invoke() with ReactTestUtils.act() so you don't need to manually wrap it.

A common pattern to trigger handlers with .act() and assert is:

const wrapper = mount(<SomeComponent />);
act(() => wrapper.prop('handler')());
wrapper.update();
expect(/* ... */);

We cannot wrap the result of .prop() (or .props()) with .act() in Enzyme internally since it will break the equality of the returned value. However, you could use .invoke() to simplify the code:

const wrapper = mount(<SomeComponent />);
wrapper.invoke('handler')();
expect(/* ... */);

Future

Enzyme Future

Contributing

See the Contributors Guide

In the wild

Organizations and projects using enzyme can list themselves here.

License

MIT

enzyme (enzymejs/enzyme)

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Enzyme
Что это такое?Enzyme — это JavaScript-утилита для тестирования React, которая упрощает проверку того, что выдают ваши React-компоненты. Она также позволяет изменять и обходить результат рендеринга и в некоторых случаях имитировать поведение во время выполнения.
Это тестовый фреймворк, который заменит мой текущий набор инструментов, или его используют вместе с ним?Это набор утилит, которые вы добавляете к уже имеющейся настройке: Enzyme не навязывает тест-раннер и библиотеку проверок (assertions) и работает со всеми основными. В собственной документации и примерах используются Mocha и Chai.
Как подключить его в React-проекте?Установите enzyme и официальный адаптер, соответствующий вашей версии React (например, enzyme-adapter-react-16), затем один раз зарегистрируйте адаптер через верхнеуровневый API configure(...).
Работают ли React Hooks, когда я тестирую код через Enzyme?Да, но с ограничениями в .shallow(): useEffect() и useLayoutEffect() не вызываются, а useCallback() не мемоизирует. На React 16.8+ при использовании .mount() Enzyme сам оборачивает вызовы вроде .simulate() и .setProps() в ReactTestUtils.act().
Он подходит только для обычного React или можно тестировать и компоненты React Native?React Native поддерживается — в README есть отдельное руководство по использованию Enzyme с React Native, а также руководства для JSDOM, Karma, Webpack, Browserify, SystemJS и других настроек.
Это бесплатно, в том числе в коммерческих проектах?Да — Enzyme распространяется по лицензии MIT, поэтому её можно свободно использовать для любых целей, включая коммерческие проекты.
Как на самом деле устроен API?Он намеренно повторяет API jQuery для работы с DOM и её обхода, поэтому если вы пользовались jQuery, поиск и изучение отрендеренных компонентов покажутся привычными и гибкими.
Какими способами можно отрендерить компонент в тесте?В документации описаны три подхода, у каждого свой раздел в документации API: поверхностный рендеринг (shallow rendering), полный рендеринг в DOM и статический рендеринг разметки.
А можно использовать его с Preact или Inferno вместо React?Да, через адаптеры от сообщества: enzyme-adapter-preact-pure для Preact стабилен, а enzyme-adapter-inferno для Inferno пока в разработке.
Есть ли вспомогательные пакеты для моей библиотеки проверок?Да — chai-enzyme (Mocha/Chai), jasmine-enzyme (Jasmine), jest-enzyme (Jest), should-enzyme (should.js) и expect-enzyme (expect) добавляют кастомные проверки и удобные функции.
What are similar projects?javascript-testing-best-practices, ava, mocha, vitest, pytest, supertest, ignite, js-stack-from-scratch
Which topics is it in?mocha, test, preact, jest, jquery, react-components, unit-testing, react-native, testing, react, npm, frontend
Creator
enzymejs
Size
7.7 MB
Stars
19.8K
Updated
CommitOct 22
Age
10y
Commits · 90 Days