Without jsdom as default, the tests don't pass

[sebastianrothe]

If I don't choose jsdom as a default for jest, the generated tests don't pass. I get

❯❯❯❯ npm run test                                                                                     ~/D/w/s/f/s/e/sveltekit master

> [email protected] test
> NODE_OPTIONS=--experimental-vm-modules jest src --config jest.config.json

(node:87367) ExperimentalWarning: VM Modules is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
 FAIL  src/routes/index-dom.spec.ts
  Index
    once the component has been rendered
      ✕ should show the proper heading (2 ms)

  ● Index › once the component has been rendered › should show the proper heading

    The error below may be caused by using the wrong test environment, see https://jestjs.io/docs/configuration#testenvironment-string.
    Consider using the "jsdom" test environment.
    
    ReferenceError: document is not defined

      19 |
      20 |   beforeEach(() => {
    > 21 |     renderedComponent = render(Index);
         |                         ^
      22 |   });
      23 |
      24 |   describe('once the component has been rendered', () => {

      at render (node_modules/@testing-library/svelte/dist/pure.js:53:28)
      at Object.<anonymous> (src/routes/index-dom.spec.ts:21:25)

Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        3.917 s, estimated 5 s
Ran all test suites matching /src/i.

This is solved by moving the comment:

/**
 * @jest-environment jsdom
 */

to the very top of the files.