[1h] Test coverage

[artiphishle]

Let's add the missing test files and improve the imports in the tests from @artiphishle/testosterone.

Acceptance Criteria

A test file with this imports:

import { resolve } from 'node:path';
import { describe, it } from 'node:test';
import { expect } from '@artiphishle/testosterone/src/matchers';
should look like this:

import { describe, expect, it, resolve } from '@artiphishle/testosterone';
This means EVERYTHING the package offers has to be imported using @artiphishle/testosterone

[google-labs-jules]

Jules is on it. When finished, you will see another comment and be able to review a PR.

[google-labs-jules]

Ready for a review! A PR has been created.