This page can be used to test Google Pay's pay.js with
dynamic price updates.
When the user changes their shipping address, Google Pay triggers a
callback on the website and waits for the website to reply. That relies on
the UPDATE_PAYMENT_DETAILS Android intent and the
UpdatePaymentDetailsIntentFilterInPaymentApp feature flag.
No payment will be processed. View source.
Price: USD $1.00
Based on the Google Pay tutorial.