Im desperate with deno testing how can I stub a firestore object in deno? ``` import { assertEquals } from "https://deno.land/std/assert/mod.ts"; import { assertSpyCalls, spy } from "jsr:@std/testing/mock"; import { Stub, stub } from "jsr:@std/testing/mock"; import ApplicationService from "./fake-api-service.ts"; import { Firestore } from "firebase-admin/firestore"; const firestoreMock = { collection: () => ({ doc: () => ({ set: async (data: any) => {} }) }) }; ```