online2.test.ts

describe("my functions", () => {
  let adminStub, api;

  beforeAll(() => {
    // you can use `sinon.stub` instead
    adminStub = jest.spyOn(admin, "initializeApp");

    // after initializeApp call, we load our functions
    api = require("../index");
  });

  afterAll(() => {
    // clean things up
    adminStub.mockRestore();
    testEnv.cleanup();

    // reset our database
    admin
      .database()
      .ref("users")
      .remove();
  });

  it("should store user in db on GoogleOAuth", async () => {
    const wrapped = testEnv.wrap(api.onUserCreate);

    const testUser = {
      uid: "122",
      displayName: "lee"
    };

    // wrap your `onUserCreate` method and pass parameter: user
    // for the sake of brevity, I omitted other `UserRecord` properties.
    // you can check https://firebase.google.com/docs/reference/js/firebase.User for more information
    await wrapped(testUser);

    // we read our user from database
    const createdUser = await admin
      .database()
      .ref(`/users/${testUser.uid}`)
      .once("value");

    // we expect our newly created user to have zero points
    expect(createdUser.val()).toHaveProperty("points", 0);
  });
});