assert

import { strictEqual, deepStrictEqual, ok, doesNotReject } from "node:assert";

strictEqual(1, 1); // ok!
strictEqual(1, "1"); // fails! throws AssertionError

deepStrictEqual({ a: { b: 1 } }, { a: { b: 1 } }); // ok!
deepStrictEqual({ a: { b: 1 } }, { a: { b: 2 } }); // fails! throws AssertionError

ok(true); // ok!
ok(false); // fails! throws AssertionError

await doesNotReject(async () => {}); // ok!
await doesNotReject(async () => {
  throw new Error("boom");
}); // fails! throws AssertionError