Abort signal is ignored when iterable doesn't yield anything

[gnarea]

The first test times out and the second passes:

import { PassThrough } from 'stream';

import { source as makeSourceAbortable } from 'abortable-iterator';

test('Empty source', async () => {
  const source = new PassThrough();
  const abortController = new AbortController();
  const abortableSource = makeSourceAbortable(source, abortController.signal, {
    returnOnAbort: true,
  });
  setImmediate(() => abortController.abort());
  for await (const chunk of abortableSource) {
    throw new Error(`Shouldn't have got ${chunk}`);
  }
});

test('Non-empty source', async () => {
  const source = new PassThrough();
  const abortController = new AbortController();
  const abortableSource = makeSourceAbortable(source, abortController.signal, {
    returnOnAbort: true,
  });
  setImmediate(() => {
    source.write('foo');
    abortController.abort();
  });
  for await (const chunk of abortableSource) {
    expect(chunk).toBe('foo');
  }
});

[achingbrain]

Is this still a problem? I've refactored the first test to not have any node-specific code and it passes:

import all from 'it-all'
import delay from 'delay'
import { abortableSource } from 'abortable-source'
import { expect } from 'aegir/chai'

it('should return with an empty source', async () => {
  const abortController = new AbortController();
  const source = abortableSource(async function * () {
    await delay(1000)
    yield 'foo'
  }(), abortController.signal, {
    returnOnAbort: true,
  })

  setTimeout(() => {
    abortController.abort()
  }, 0)

  // should be empty since the signal was aborted before any value was yielded
  const result = await all(source)
  expect(result).to.have.lengthOf(0)
})