#testing-library/jest-dom not loading - reactjs

Question

I'm trying to introduce React Testing Library into Create React App project, and I'm hitting a strange problem. For one of my tests, I need to use jest-dom, but I can't seem to import it successfully.
I've yarn add'ed it, and can't think of what step I missed.
expect.extend fails because its toHaveStyle is undefined.
Here's my test file, reduced down to the minimum:
import React from 'react';
import {render, screen} from '#testing-library/react';
import {toHaveStyle} from '#testing-library/jest-dom';
import '#testing-library/jest-dom/extend-expect';
//expect.extend({toHaveStyle});
it('is confusing me', () => {
// (Using `toBe(42) as an ersatz `console.log`)
expect([Object.keys(require('#testing-library/jest-dom')), Object.keys(require('#testing-library/react')), toHaveClass]).toBe(42);
});
The output is:
Expected: 42
Received: [[], ["render", "cleanup", "fireEvent", ...], undefined]
And, here's the relevant part of yarn.lock:
"#testing-library/jest-dom#^5.7.0":
version "5.7.0"
resolved "https://registry.yarnpkg.com/#testing-library/jest-dom/-/jest-dom-5.7.0.tgz#b2e2acb4c088a293d52ba2cd1674b526282a2f87"
integrity sha512-ZV0OtBXmTDEDxrIbqJXiOcXCZ6aIMpmDlmfHj0hGNsSuQ/nX0qPAs9HWmCzXvPfTrhufTiH2nJLvDJu/LgHzwQ==
dependencies:
"#babel/runtime" "^7.9.2"
"#types/testing-library__jest-dom" "^5.0.2"
chalk "^3.0.0"
css "^2.2.4"
css.escape "^1.5.1"
jest-diff "^25.1.0"
jest-matcher-utils "^25.1.0"
lodash "^4.17.15"
redent "^3.0.0"
"#testing-library/react#^10.0.4":
version "10.0.4"
resolved "https://registry.yarnpkg.com/#testing-library/react/-/react-10.0.4.tgz#8e0e299cd91acc626d81ed8489fdc13df864c31d"
integrity sha512-2e1B5debfuiIGbvUuiSXybskuh7ZTVJDDvG/IxlzLOY9Co/mKFj9hIklAe2nGZYcOUxFaiqWrRZ9vCVGzJfRlQ==
dependencies:
"#babel/runtime" "^7.9.6"
"#testing-library/dom" "^7.2.2"
"#types/testing-library__react" "^10.0.1"

Answer 1

Well, jest-dom documentation has been updated.
import {toHaveStyle} from '#testing-library/jest-dom';
would not work anymore. Instead,
import {toHaveStyle} from '#testing-library/jest-dom/matchers'
For reference, see jest-dom

Answer 2

Here is how I use this great library :
// in test file
import '#testing-library/jest-dom/extend-expect';
[...]
// then matchers are available in tests
expect(rtl.getByText('text').toHaveClass('some-class');
My import is slightly different than yours, I could not say precisely what goes wrong with yours but this is how I do.
Good luck !

Answer 3

module not found can't resolve node_modules\react-scripts\node_modules\babel-loader\lib\index.js' in react 17
Okay so if there is anyone looking at this in 2022+ year, After downgrading from react-v18 to react-v17 I faced this issue. I had to run certain commands.
npm install web-vitals#1.0.1
npm install babel-loader --save-dev
npm install -D babel-loader #babel/core #babel/preset-env webpack
I also moved my #testing-library/jest-dom,#testing-library/react,#testing-library/user-event to devDependencies and downgraded them
Worked like a charm.