QueryDocumentSnapshot that passed to trigger functions doesn't contain createTime element

[Prabhath Darshana]

Description

QueryDocumentSnapshot that passed to trigger functions doesn't contain createTime element

Steps to reproduce

Call createTime in snapshot passed into a trigger function.

Expected result

The createTime should contain a value of the document created in the original scenario.
https://googleapis.dev/nodejs/firestore/latest/QueryDocumentSnapshot.html

Actual result

createTime element is not available within the queryDocumentSnapshot that passed to trigger functions

Fix suggesstion

For mocking purposes, we can provide the current time of the test suit or createdAt time if available on the FakeFirestore database.
In order to correct the issue, buildDocFromHash.js file should return an object containing populated createTime.
For example:

module.exports = function buildDocFromHash(hash = {}, id = 'abc123') {
  const exists = !!hash || false;
  return {
    exists,
    id: (hash && hash.id) || id,
    ref: hash && hash._ref,
    createTime: hash.createdAt,
    metadata: {
      hasPendingWrites: 'Server',
    },
  ...

[Scott Batson]

Fixed by #127