Advice regarding indeterminate callbacks

[natzcam]

How best to approach this?

test.cb('2 callbacks', t => {
    t.plan(2);

    const alice = new Alice();
    alice.on('connect', () => {
        t.pass();
        t.end(); //?
    });

    const bob = new Bob();
    bob.on('connect', () => {
        t.pass();
        t.end(); //?
    });
});

There is no guarantee which connect callback will be called first, but I need to assert that both got called. Promise.all could solve this but are there any alternatives?

[havenchyk]

@natzcam I don't know the answer except using Promise.all, but the best place for asking such questions is https://spectrum.chat/ava or stackoverflow.

Btw, if you could split this logic into 2 tests it would be easier to track/manipulate from the first sight.

[novemberborn]

You could also count how many connects are still pending, decrement on each connect and within that callback if you hit zero, call t.end().

None of this helps if a callback is invoked twice though.

(I'm closing this issue for housekeeping purposes, but let's keep the conversation going.)

[novemberborn]

You could also count how many connects are still pending, decrement on each connect and within that callback if you hit zero, call t.end().

None of this helps if a callback is invoked twice though.

(I'm closing this issue for housekeeping purposes, but let's keep the conversation going.)

[sindresorhus]

You could also use p-event for this:

import test from 'ava';
import pEvent from 'p-event';

test('2 callbacks', async t => {
	const alice = new Alice();
	await pEvent(alice, 'connect');

	const bob = new Bob();
	await pEvent(bob, 'connect');

	t.pass();
});

[natzcam]

Tried above, but the test would not complete because connection is initiated on the constructor and await pEvent(alice, 'connect'); would block new Bob(). Changing the order did not help either, because 'connect' might have been fired already.

  const alice = new Alice();
  const bob = new Bob();
  await pEvent(alice, 'connect');
  await pEvent(bob, 'connect');
  t.pass();

Using Promise.all would solve it though, but it would circle back to my original question. :)

  await Promise.all([pEvent(alice, 'connect'), pEvent(bob, 'connect')]);
  t.pass();

It would be nice, for callbacks, there is a 'countdown' functionality. Wherein, the test would end when the countdown = 0

test.cb('2 callbacks', t => {
    t.plan(2);
    t.countdown(2);

    const alice = new Alice();
    alice.on('connect', () => {
        t.pass();
        t.end(1); //decrement 1
    });

    const bob = new Bob();
    bob.on('connect', () => {
        t.pass();
        t.end(1); //decrement 1
    });
});

[novemberborn]

I think that's functionality one could add atop of AVA once #1692 lands.