I can’t unit test my Google Cloud Functions in online mode (as defined in the instructions that I followed: https://firebase.google.com/docs/functions/unit-testing): if I navigate to the functions folder and run npm run test, I get:

> test
> mocha --reporter spec

Error: No test files found

The problem could be with the fact that I’m using writing both test and production code in Typescript, while the documentation I followed only focuses on Javascript.

Here is part of my project structure, if it makes sense:

I can call functions just fine from my UIKit app, even using the emulator suite.

Here is an example function in Typescript:

import { Request, Response } from 'express';

export const helloWorld = (req: Request, res: Response) => {
    res.send('Hello, World!');
};

And here is an example test in Typescript:

// use your actual details
const test = require('firebase-functions-test')({
  databaseURL: 'https://my-project.firebaseio.com',
  storageBucket: 'my-project.appspot.com',
  projectId: 'my-project',
}, 'path/to/serviceAccountKey.json');

import * as mocha from "mocha";
import * as chai from "chai";
// be sure to only do this after initializing firebase-functions-test, and mocking config values.
import * as functions from "../src/index";

import { Request, Response } from 'express';

describe('helloWorld function', () => {
  it('should send "Hello, World!"', () => {
    const req = {} as Request;
    const res = {
      send: (message: string) => {
        chai.expect(message).to.equal('Hello, World!');
      }
    } as Response;

    functions.helloWorld(req, res);
  });
});

These posts only gave rise to other problems for me: mocha Error: No test files found: “test/” npm ERR! Test failed.
No test files found: “test” when testing security rules using Mocha using Typescript