support returning promises from dynamic fixtures

[christopherjbaker]

This would allow a lot more flexibility in the use of fixtures, including allowing fixtures to depend on each other, creating route-specific delays, and even allowing resolution from external sources. It would also make it integrate nicely with async/await without adding weight to the library.

fixture('/', async (req, res) => {
  await wait(5000);
  return res({
    foo: 'bar'
  });
});

[chasenlehara]

This is a great addition! Let’s get this merged in as soon as docs are added.

[christopherjbaker]

I've got a bit to catch up on with my client, but Ill try to get docs in this week.

[chasenlehara]

👍 Left one suggestion.