Why does jest doesn't fail with process.nextTick?

Question

I was trying to solve an issue for jest's detection of open handles when using async for external API. I did find a solution here that using process.nextTick solves the problem. I understand that this adds an empty function to be executed immediately after the event loop finishes, but how does this solve the issue?

Tests fail with this code:

(async function myFunc() {
  try {
    let config = await s3.getObject({
      Bucket: `bucketname`,
      Key: `key`,
    }).promise();
      ^ open handle is detected here
    ...more code

  } catch (e) {
    console.log(e)
  }
})();

Tests pass with this code:

(async function myFunc() {
  try {
    await process.nextTick(() => { }) // <- added this line
    let config = await s3.getObject({
      Bucket: `bucketname`,
      Key: `key`,
    }).promise();
      ^ open handle is detected here
    ...more code

  } catch (e) {
    console.log(e)
  }
})();