How to use createTranspilingRequire method in Jest

You can create a jest config file jest.config.js and put the following entry into it:

module.exports = {
  ...
  setupFiles: ['<rootDir>/test/setup.js'],
  ...
};

And then in your setup.js file, you can do something like this:

process.on('unhandledRejection', (err) => {
  fail(err);
});

And unhandledRejection will fail a test, though there are two caveates to be aware of:

1. Unhandled rejections from promises that reject when there is no test running will end the process. This is probably what you want and expect.
2. Unhandled rejections from promises that reject when a new test is running (not the one that initiated the promise) will fail the new test, not the original test. This is confusing and can make for difficult to track bugs.

As a commenter mentioned above, if your tests are well written, then you should never hit this scenario, but you don't always have that much control.

@gillyb is right just forgot to "mock" the Foo module

// Foo.js
export class Foo {
    public static bar() {
        doSomething();
    }

    constructor(paramA, paramB) {

    } 
}

// Foo.spec.js
import Foo from './Foo.js';
jest.mock('./Foo.js');

it('test something...', () => {
    // Assuming we did something that called our constructor
    expect(Foo).toHaveBeenCalledTimes(1);
});

'11 111.11'.split('').map(x => console.log((x.charCodeAt(0))))

Yields "32" for the space character which is a normal space.

new Intl.NumberFormat('fr-CA').format(11111.11).split('').map(x => console.log((x.charCodeAt(0))))

Yields "160" for the space character, which is a non-breaking space.

To make these tests pass, you need to add the non-breaking space UTF-16 (\xa0) character code into the assertion.

expect(formatCurrency(24555.55, 'fr_CA', true)).toBe('24\xa0555,55 $');

I use "waitForSelector" method and after that try to get the text

await page.waitForSelector('your selector')
let element = await page.$('your selector')
let value = await page.evaluate(el => el.textContent, element)

I solved this issue using:

• npm uninstall -g jest
• npm install -g jest
• npm cache clean
• npm install

scrollIntoView is not implemented in jsdom. Here's the issue: link.

You might get it working by manually adding it:

window.HTMLElement.prototype.scrollIntoView = function() {};

Node

If you want to run them directly through node, try to require jest and/or jest-runtime. Also give @types/jest a try as well.

Check Edit 2 for new info about this

Edit

@types/jest (jest-DefinitelyTyped) is definitely needed (or just one solution). If you install it (e.g., dev dependency), the IDE errors should go away. I just tried it on Webstorm, and it works.

Edit 2

The new Jest@20 Matchers (e.g., .resolves and .rejects) are still not defined in @types/jest. You can keep track of its status on the links below: https://github.com/DefinitelyTyped/DefinitelyTyped/pull/16645 https://github.com/DefinitelyTyped/DefinitelyTyped/issues/16803

It should be available soon, though!

Also, it doesn't seem possible to run it directly through node. Last night I tried a bunch of different things, but using jest is the way to go - it really uses node under the hood, so I thought it would be possible as well. @thymikee over your opened issue at GitHub made clear that it's not.

Edit 3

The new release (20.0.1) includes the newest Jest definitions.

Lint

this isn't in the scope of this specific problem, but it also helps

Are you using something like ESLint? If so, you'll need eslint-plugin-jest

Following the steps described in this page: https://www.npmjs.com/package/eslint-plugin-jest, you will basically need to add it as an ESLint plugin and set jest globals in the ESLint configuration:

{
  "env": {
    "jest/globals": true
  }
}

If you plan on supporting ES6 tests, you'll also need Babel and babel-jest plugin with the following jest configuration:

"transform": {
  "^.+\\.js$": "babel-jest"
}

Finally, for Typescript tests you'd need the @types/jest and ts-jest packages as well

Run your sass/css files to show all space characters. I am pretty sure there is a non-breaking space somewhere between your properties which is causing it to break. something like

{
  color:[non-breaking-space]#123456;
}

You can spot these bad characters by installing a VS code plugin called Highlight Bad Chars https://marketplace.visualstudio.com/items?itemName=wengerk.highlight-bad-chars

You have to provide initialEntries as well as initialIndex. In your case it should look like this:

const wrapper = shallow(
  <MemoryRouter initialEntries={['/']} initialIndex={0}>
    <App/>
  </MemoryRouter>
);

Other possibility is that you need enzyme's mount instead of shallow.

react-router has some great documentation here: https://reacttraining.com/react-router/core/api/MemoryRouter