We provide a testing environment which is running independently from the real Bitcoin network and it's running against Bitcoin testnet.
For testing we recommend using either
bitcoin-qt wallet in the testnet mode or Bitcoin Wallet for Testnet which is an Android wallet running on the phone.
The testnet Bitcoins are free and can be requested here:
Our Demo store application is running here: https://demo-store.bitcoinpaygate.com/
See Demo Integration for more details.
To see payment notifications you can use Request Bin - just pass a generated URL as notification URL