bluebill1049 bluebill1049 - 3 months ago 10
React JSX Question

Test with reactjs renderIntoDocument keep failed due to required DOM

I am new to reactJS and try to learn how to test with it. I have encouter the following testing util method. However i am keep getting the same error

message:ReferenceError: document is not defined
.




renderIntoDocument

ReactComponent renderIntoDocument(
ReactElement instance
)


Render a component into a detached DOM node in the document. This function requires a DOM.

Note:
You will need to have window, window.document and window.document.createElement globally available before you import React. Otherwise React will think it can't access the DOM and methods like setState won't work.




I know it the reason failing its missing the DOM, but how can i insert the DOM or require it?




My test below:

import expect from 'expect.js';
import React from 'react';
import Header from '../../components/header';
import {renderShallow} from './help';
import ReactAddOn from 'react/addons';

var TestUtils = ReactAddOn.addons.TestUtils;

describe('Test react', function() {
let component;

beforeEach(()=>{
component = TestUtils.renderIntoDocument(<Header></Header>);
});


it('Test if the content been correclty render', function() {
console.log(component);
});
});

Answer

tl;dr; You need jsdom + Mocha.


According to spec ReactTestUtils#renderIntoDocument,

renderIntoDocument() requires a DOM:

You will need to have window, window.document and window.document.createElement globally available before you import React. Otherwise React will think it can't access the DOM and methods like setState won't work.

Traditionally, Unit testing in React is done using Jest, which apparently contains DOM support. And Mocha doesn't.

To understand this, consider this overly simplify analogy, Jest = Mocha + jsdom.

jsdom is implemented in JavaScript, we can have a DOM-like API to work with without needing a browser. That means that we don’t have to capture a browser in order test, like Karma (which is why it works the moment you use Karma). Hence, we can run our tests in environments without browsers, like in Node or in continuous integration environments.


References:

  1. Tutorial: Testing React on Jsdom
  2. React Spec: ReactTestUtils#renderIntoDocument
  3. Information: How to Jest
  4. Information: react-testing-mocha-jsdom
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