Support firebase-admin v14

[ChromeQ]

Since firebase-admin was updated to v14 then my tests have been throwing a type error with this package.

Here is a simple reproduction test:

import { onDocumentWritten } from 'firebase-functions/firestore';
import functions from 'firebase-functions-test';
import { getFirestore } from 'firebase-admin/firestore';

const testHandler = onDocumentWritten(
  {
    document: 'test-col/{id}',
  },
  (event) => {
    const before = event.data?.before.data();
    const after = event.data?.after.data();

    console.log('Before:', before);
    console.log('After:', after);
  }
);

it('should run this test', async () => {
  const wrapped = functions().wrap(testHandler);
  const ref = getFirestore().collection('test-col').doc('test-id');

  await ref.set({ foo: 'bar' });

  const beforeSnap = testEnv.firestore.makeDocumentSnapshot({}, ref.path); // 👈 error line
  const afterSnap = await ref.get();
  const change = testEnv.makeChange(beforeSnap, afterSnap);

  await wrapped({ data: change });
});

This is the error thrown when running the test:

TypeError: (0 , firebase_admin_1.firestore) is not a function
 ❯ Object.makeDocumentSnapshot ../node_modules/.pnpm/firebase-functions-test@3.5.0_firebase-admin@14.1.0_firebase-functions@7.2.5_firebase-a_0f4ad8eb00077a7969708a21d93a6210/node_modules/firebase-functions-test/lib/providers/firestore.js:59:59

---

Additional Note:

Whilst fixing this, would it be possible to correctly type the return type of makeDocumentSnapshot rather than any? Very strict TS projects don't like any.

firebase-functions-test/src/providers/firestore.ts

Line 68 in e74c0b5

export function makeDocumentSnapshot(

The declaration file ends up with any despite the exampleDocumentSnapshot returning firestore.DocumentSnapshot type when it just calls makeDocumentSnapshot - so makeDocumentSnapshot should also return firestore.DocumentSnapshot right?

// node_modules/firebase-functions-test/lib/providers/firestore.d.ts#16

/** Create a DocumentSnapshot. */
export declare function makeDocumentSnapshot(
/** Key-value pairs representing data in the document, pass in `{}` to mock the snapshot of
 * a document that doesn't exist.
 */
data: {
    [key: string]: any;
}, 
/** Full path of the reference (e.g. 'users/alovelace') */
refPath: string, options?: DocumentSnapshotOptions): any;
/** Fetch an example document snapshot already populated with data. Can be passed into a wrapped
 * Firestore onCreate or onDelete function.
 */
export declare function exampleDocumentSnapshot(): firestore.DocumentSnapshot;

[IzaakGough]

Hi @ChromeQ, thanks for raising this. We will review as soon as possible.