'it' is not defined

[bsastregx]

Greetings all,

I am trying to run a test using web-test-runner. I am following the steps from this documentation: https://modern-web.dev/guides/test-runner/getting-started/

The documentation instructs to install the necessary packages:
npm i --save-dev @web/test-runner @esm-bundle/chai

Then writting the test with the required imports:

import { expect } from '@esm-bundle/chai';
import { sum } from '../src/sum.js';

it('sums up 2 numbers', () => {
  expect(sum(1, 1)).to.equal(2);
  expect(sum(3, 12)).to.equal(15);
});

Now, I am getting a warning, that 'it' is not defined:
'it' is not defined.

Of course is not, since I didn't import it.

• Where should I import this function from?
• Why does the documentation gives a code example that uses a function that is not installed/included? This causes confusion.

Thanks in advance!