There are two methods to add test users to your Google Home Action.

Method 1: Adding Testers via Google Cloud Platform (GCP) This method allows you to add a limited number of testers directly in the Google Cloud Platform (GCP) for your project. Steps:

1. Log in to the Google Cloud Platform Console for your project.
2. Navigate to IAM & Admin > IAM in the left-hand menu.
3. Click on Grant access for your project.
4. In the “Add principals” section, enter the email address of the tester.
5. Assign the “Viewer” role to the tester.
6. Click Save to finalize the process.

Images for reference: Grant access in View by principals Add test users

Method 2: Using Field Trials via Matter For larger testing efforts or when working with Matter-supported devices, using Field Trials is the recommended method. This process is integrated into the Matter section of the Google Home Developer Console. Steps:

1. Go to the Google Home Developer Console.
2. Navigate to Matter > Test > Field Trials in the left-hand menu.
3. Click on Run a Field Trial.
4. Add the testers by entering their email addresses and assign the necessary permissions for testing.

Images for reference: Matter console Field Trail