diff --git a/packages/@uppy/companion-client/src/Provider.js b/packages/@uppy/companion-client/src/Provider.js
index 88969b1d0a..5a088fa274 100644
--- a/packages/@uppy/companion-client/src/Provider.js
+++ b/packages/@uppy/companion-client/src/Provider.js
@@ -160,8 +160,9 @@ export default class Provider extends RequestClient {
     await this.#refreshingTokenPromise
 
     try {
-      // throw Object.assign(new Error(), { isAuthError: true }) // testing simulate access token expired (to refresh token)
-      // A better way to test this is for example with Google Drive:
+      // to test simulate access token expired (leading to a token token refresh),
+      // see mockAccessTokenExpiredError in companion/drive.
+      // If you want to test refresh token *and* access token invalid, do this for example with Google Drive:
       // While uploading, go to your google account settings,
       // "Third-party apps & services", then click "Companion" and "Remove access".
 
diff --git a/packages/@uppy/companion/src/server/provider/drive/index.js b/packages/@uppy/companion/src/server/provider/drive/index.js
index a5dd5f185f..f0b4e9a850 100644
--- a/packages/@uppy/companion/src/server/provider/drive/index.js
+++ b/packages/@uppy/companion/src/server/provider/drive/index.js
@@ -5,6 +5,16 @@ const logger = require('../../logger')
 const { VIRTUAL_SHARED_DIR, adaptData, isShortcut, isGsuiteFile, getGsuiteExportType } = require('./adapter')
 const { withProviderErrorHandling } = require('../providerErrors')
 const { prepareStream } = require('../../helpers/utils')
+const { ProviderAuthError } = require('../error')
+
+
+// For testing refresh token:
+// first run a download with mockAccessTokenExpiredError = true 
+// then when you want to test expiry, set to mockAccessTokenExpiredError to the logged access token
+// This will trigger companion/nodemon to restart, and it will respond with a simulated invalid token response
+const mockAccessTokenExpiredError = undefined
+// const mockAccessTokenExpiredError = true
+// const mockAccessTokenExpiredError = ''
 
 const DRIVE_FILE_FIELDS = 'kind,id,imageMediaMetadata,name,mimeType,ownedByMe,size,modifiedTime,iconLink,thumbnailLink,teamDriveId,videoMediaMetadata,shortcutDetails(targetId,targetMimeType)'
 const DRIVE_FILES_FIELDS = `kind,nextPageToken,incompleteSearch,files(${DRIVE_FILE_FIELDS})`
@@ -117,6 +127,15 @@ class Drive extends Provider {
   }
 
   async download ({ id: idIn, token }) {
+    if (mockAccessTokenExpiredError != null) {
+      logger.warn(`Access token: ${token}`)
+
+      if (mockAccessTokenExpiredError === token) {
+        logger.warn('Mocking expired access token!')
+        throw new ProviderAuthError()
+      }
+    }
+
     return this.#withErrorHandling('provider.drive.download.error', async () => {
       const client = getClient({ token })