react-testing-library why is toBeInTheDocument() not a function

Question

Here is my code for a tooltip that toggles the CSS property display: block on MouseOver and on Mouse Out display: none.

 it(\'should sho         


        

Answer 1

If you don't already have jest-dom installed, you need to install it using the command below.

npm i --save-dev @testing-library/jest-dom

create a file in the root of your project folder and name it jest-setup.js. Your file should have the following content.

import "@testing-library/jest-dom/extend-expect";

In your package.json, add the code below to your jest config;

"jest": {
    "setupFilesAfterEnv": ["/jest-setup.js"]
}