I'm attempting to test a React component with Jest/Enzyme while using Webpack.
I have a very simple test @
import React from 'react';
import { shallow } from 'enzyme';
import App from './App';
it('App', () => {
const app = shallow(<App />);
expect(1).toEqual(1);
});
The relative component it's picking up is :
import React, { Component } from 'react';
import { render } from 'react-dom';
// import './styles/normalize.css';
class App extends Component {
render() {
return (
<div>app</div>
);
}
}
render(<App />, document.getElementById('app'));
However, running jest causes a failure:
Invariant Violation: _registerComponent(...): Target container is not a DOM element.
With errors @
at Object.<anonymous> (src/App.js:14:48)
at Object.<anonymous> (src/App.test.js:4:38)
The test files references line 4, which is the import of <App />, that causes a fail. The stack trace says line 14 of App.js is the reason for the failure -- which is nothing more than the render call from react-dom, something I've never had a challenge with (the app renders properly from my Webpack setup).
For those interested (Webpack code):
module.exports = {
entry: './src/App',
output: {
filename: 'bundle.js',
path: './dist'
},
module: {
loaders: [
{
test: /.js?$/,
exclude: /node_modules/,
loader: 'babel',
query: {
presets: ['react', 'es2015']
}
},
{
test: /.css$/,
loader: 'style!css-loader?modules&importLoaders=1&localIdentName=[name]__[local]___[hash:base64:5]'
},
{
test: /.scss$/,
loader: 'style!css-loader?modules&importLoaders=1&localIdentName=[name]__[local]___[hash:base64:5]!sass'
}
]
}
}
And my package.json:
{
"name": "tic-tac-dux",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"dev": "webpack-dev-server --devtool eval --progress --colors --inline --hot --content-base dist/",
"test": "jest"
},
"jest": {
"moduleNameMapper": {
"^.+\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/__mocks__/fileMock.js",
"^.+\.(css|sass)$": "<rootDir>/__mocks__/styleMock.js"
}
},
"keywords": [],
"author": "",
"license": "ISC",
"devDependencies": {
"babel-core": "^6.17.0",
"babel-jest": "^16.0.0",
"babel-loader": "^6.2.5",
"babel-polyfill": "^6.16.0",
"babel-preset-es2015": "^6.16.0",
"babel-preset-react": "^6.16.0",
"css-loader": "^0.25.0",
"enzyme": "^2.4.1",
"jest": "^16.0.1",
"jest-cli": "^16.0.1",
"node-sass": "^3.10.1",
"react-addons-test-utils": "^15.3.2",
"react-dom": "^15.3.2",
"sass-loader": "^4.0.2",
"style-loader": "^0.13.1",
"webpack": "^1.13.2",
"webpack-dev-server": "^1.16.2"
},
"dependencies": {
"react": "^15.3.2",
"react-dom": "^15.3.2"
}
}
Oh, and if anyone is going to say that the div element isn't being loaded before the script, here's my index.html:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>App</title>
</head>
<body>
<div id="app"></div>
<script src="/bundle.js"></script>
</body>
</html>
What could be the reason for this peculiar rendering problem? Something to do with a new Jest update to 15.0?
See Question&Answers more detail:
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