Microticks-independent `chain`

test.js

async function chain(iterator, cancelAccessorF) {
    if (cancelAccessorF) {
        cancelAccessorF(e => {
            return Promise.reject(e);
        });
    }

    for (const p of iterator) {
        await p;
    }
}

// The first 4 tests remain the same

test("Cancelling a promise chain from a generator", async assert => {
    const {messages, resolvers, promises, promiseGenerator} = setup();

    let cancel = () => {};
    // Unfortunatelly we can't use the .finally on `chain` itself
    // but instead we use try..catch..finally around the cancellation
    chain(promiseGenerator(), c => cancel = c);

    resolvers[0]();
    await promises[0];

    try {
        await cancel({tutorialId: 2});
    } catch (e) {
        // Here we get the cancelled tutorial as `e`
        console.log('<catch handler> Tutorial:', e);
    } finally {
        assert.deepEqual(messages, ["Before promise 1", "Before promise 2"]);
        assert.end()
    }
});