Apple Pay – mobile payment technology
Testing Apple Pay Transactions
Use the Apple Pay Sandbox environment to test your transactions with test payment cards.
In iTunes Connect, create a test account. This account works for both App Store and Apple Pay testing.
On a valid test device, log into iCloud using the test account.
In the Wallet app, add a new card using manual entry.
Logging in and out of your iCloud account removes your cards.
Tips: Don’t forget to enable the Apple Pay capabilities in Xcode.
More details: https://developer.apple.com/