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.
Are you here to check whether or not Enzyme is compatible with React 16? Are you currently using Enzyme 2.x? Great! Check out ourmigration guidefor help moving on to Enzyme v3 where React 16 is supported.
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-16Each adapter may have additional peer dependencies which you will need to install as well. For instance,
enzyme-adapter-react-16has peer dependencies onreactandreact-dom.
At the moment, Enzyme has adapters that provide compatibility withReact 16.x,React 15.x,
React 0.14.xandReact 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 levelconfigure(...)API.
importEnzymefrom'enzyme';
importAdapterfrom'enzyme-adapter-react-16';
Enzyme.configure({adapter:newAdapter()});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) |
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 useMochaandChai,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:
chai-enzymewith Mocha/Chai.jasmine-enzymewith Jasmine.jest-enzymewith Jest.should-enzymefor should.js.expect-enzymefor expect.
Using Enzyme with React Native
Using Enzyme with Tape and AVA
importReactfrom'react';
import{expect}from'chai';
import{shallow}from'enzyme';
importsinonfrom'sinon';
importMyComponentfrom'./MyComponent';
importFoofrom'./Foo';
describe('<MyComponent />',()=>{
it('renders three <Foo /> components',()=>{
constwrapper=shallow(<MyComponent/>);
expect(wrapper.find(Foo)).to.have.lengthOf(3);
});
it('renders an `.icon-star`',()=>{
constwrapper=shallow(<MyComponent/>);
expect(wrapper.find('.icon-star')).to.have.lengthOf(1);
});
it('renders children when passed in',()=>{
constwrapper=shallow((
<MyComponent>
<divclassName="unique"/>
</MyComponent>
));
expect(wrapper.contains(<divclassName="unique"/>)).to.equal(true);
});
it('simulates click events',()=>{
constonButtonClick=sinon.spy();
constwrapper=shallow(<FooonButtonClick={onButtonClick}/>);
wrapper.find('button').simulate('click');
expect(onButtonClick).to.have.property('callCount',1);
});
});Read the fullAPI Documentation
importReactfrom'react';
importsinonfrom'sinon';
import{expect}from'chai';
import{mount}from'enzyme';
importFoofrom'./Foo';
describe('<Foo />',()=>{
it('allows us to set props',()=>{
constwrapper=mount(<Foobar="baz"/>);
expect(wrapper.props().bar).to.equal('baz');
wrapper.setProps({bar:'foo'});
expect(wrapper.props().bar).to.equal('foo');
});
it('simulates click events',()=>{
constonButtonClick=sinon.spy();
constwrapper=mount((
<FooonButtonClick={onButtonClick}/>
));
wrapper.find('button').simulate('click');
expect(onButtonClick).to.have.property('callCount',1);
});
it('calls componentDidMount',()=>{
sinon.spy(Foo.prototype,'componentDidMount');
constwrapper=mount(<Foo/>);
expect(Foo.prototype.componentDidMount).to.have.property('callCount',1);
Foo.prototype.componentDidMount.restore();
});
});Read the fullAPI Documentation
importReactfrom'react';
import{expect}from'chai';
import{render}from'enzyme';
importFoofrom'./Foo';
describe('<Foo />',()=>{
it('renders three `.foo-bar`s',()=>{
constwrapper=render(<Foo/>);
expect(wrapper.find('.foo-bar')).to.have.lengthOf(3);
});
it('renders the title',()=>{
constwrapper=render(<Footitle="unique"/>);
expect(wrapper.text()).to.contain('unique');
});
});Read the fullAPI Documentation
Enzyme supportsreact hookswith some limitations in.shallow()due to upstream issues in React's shallow renderer:
-
useEffect()anduseLayoutEffect()don't get called in the React shallow renderer.Related issue -
useCallback()doesn't memoize callback in React shallow renderer.Related issue
If you're using React 16.8+ and.mount(),Enzyme will wrap apis including.simulate(),.setProps(),.setContext(),.invoke()withReactTestUtils.act()so you don't need to manually wrap it.
A common pattern to trigger handlers with.act()and assert is:
constwrapper=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:
constwrapper=mount(<SomeComponent/>);
wrapper.invoke('handler')();
expect(/*... */);See theContributors Guide
Organizations and projects usingenzymecan list themselveshere.
