How to connect Firebase Admin to Emulator Auth

Question

I am struggling to connect to the emulated Firebase Auth service via the Firebase Admin SDK. I cut down the code to really make the problem stand out, and hope someone can help.

This is the code of the test.js I run (in NodeJS):

// Someone said these two lines should allow the firebase-admin
// SDK to connect to the emulators, but... no.
process.env['GCLOUD_PROJECT'] = 'my-firebase-project-id'
process.env['FIRESTORE_EMULATOR_HOST'] = 'localhost:8080'
const admin = require('firebase-admin')
const app = admin.initializeApp()
const auth = app.auth()
console.log('I have an auth service object')
auth.listUsers().then(users => console.log(users))

I run the emulators like this:

firebase emulators:start --only auth

When I run the test.js file, I get this:

PS C:\...\functions> node .\test.js
I have an auth service object
(node:18232) UnhandledPromiseRejectionWarning: Error: Credential implementation provided to initializeApp() via the "credential" property failed to fetch a valid Google OAuth2 access token with the following error: "Error fetching access token: Error while making request: getaddrinfo EAI_AGAIN metadata.google.internal. Error code: EAI_AGAIN".
    at FirebaseAppError.FirebaseError [as constructor] (C:\...\functions\node_modules\firebase-admin\lib\utils\error.js:44:28)
    at FirebaseAppError.PrefixedFirebaseError [as constructor] (C:\...\functions\node_modules\firebase-admin\lib\utils\error.js:90:28)
    at new FirebaseAppError (C:\...\functions\node_modules\firebase-admin\lib\utils\error.js:125:28)    
    at C:\...\functions\node_modules\firebase-admin\lib\app\firebase-app.js:87:19
    at processTicksAndRejections (internal/process/task_queues.js:97:5)

I run this on Windows with the following versions of firebase:

    "firebase-admin":     "^10.0.2",
    "firebase-functions": "^3.18.1",

I read about getting a secret credentials key and adding its path like this:

process.env['GOOGLE_APPLICATION_CREDENTIALS'] = 'C:\\...\\functions\\.runtimekey.json'

And that 'works' in as much as I then can access the real cloud auth instance (as long as the emulators is off) but that isn't what I want. I want to connect firebase-admin and get a list of users in the emulated Auth instance.

Many thanks for any help you can offer!