Node has a test runner on board whose capabilities depend on the Node version used, esp. “mock.property” requiring at least Node 22.20, and “mock” and other objects have to be imported identically to every test file.
The following acts as a tiny middleware to check the running Node version before importing the required Node functionality in single stroke.
Bun implents Node’s “assert” fully and its test runner library partly, so the bootstrap here will also accept to be run in Bun, details may depend on exact tests.
Dev dependencies like this should be installed explicitly as such to make it easier for humans and tooling to separate it from production critical / less exchangeable things, so do not dismiss the “-D” switch (“-d” for Bun) just by regarding it as old-school.
Pick for your preferred package manager:
npm i -D node-test-bootstrap
pnpm i -D node-test-bootstrap
// see note on Bun in README
bun i -D node-test-bootstrap
# For Yarn you should double check docs for your and / or
# current Yarn version, newer versions do not treat `i package_name`
# as an alias for `add ...` and exclude global installations
yarn add -D node-test-bootstrap
import { assert, mock, suite, test } from 'node-test-bootstrap';
import { /* your functions to check */ } from /* your module to check */;
suite( /* your detail test */, () => {
/* your test setup */
test( /* display name */, /* options */ , () => {
/* your details */
assert( /* your check */ )
});
});
Tests if given Node version is not older than that stated for “engines: node” in the current library’s package.json (not the package.json of the project where the current library is imported to). Literal range operators (formally required in package.json) would be stripped off since “>=” is implicit here. Note that unfortunately npm regards “engines” settings just as “advisory” and therefore will not prevent installing into not matching Node versions.
VS Code may mark a Quick Fix “Could not find a declaration file for module ‘node-test-bootstrap’” (with some non working suggestsions for fixing), while at the same time Type checking and IntelliSense work well. The background here is that the functions to type come from general Node libraries and the type definitions for them are acquired automatically by VS Code - trying to provide them by the way the Quick Fix for ts(7016) knows about would superfluously and massively blow up the size of the current package and its update cycles.