Developer Portal
12.10 Test and Production Modes
For testing, the Javascript in Section XII defaults to test mode. The directive:
paymentsClient = new google.payments.api.PaymentsClient({environment: ‘TEST’} is set to TEST mode which indicates to GOOGLE that you are in test mode allowing for the development and testing of your application.
Once the application has been approved by GOOGLE and a merchantId, merchantName has been assigned, update new paymentsClient = new google.payments.api.PaymentsClient({environment: ‘PRODUCTION’}. This will indicate this is a production environment to Google.