Any body has testnet BTC can donate?
I only own very small amount of tBTC, so i would recommend you to perform solo mining where you could get some tBTC by mining block which has difficulty 1.
Can't pay him back , all the testnet bitcoin will pay to bitpay for testing my web app
I briefly read BitPay documentation and found out it's possible to recycle/obtain tBTC you used to make payment.
In order to recycle your Bitcoin testnet coins, set your test.bitpay.com settlement address to your testnet wallet's receiving address (note: most testnet Bitcoin addresses begin with the prefix m or n rather than the prefix 1 or 3 of mainnet Bitcoin addresses) and set payment at 100% BTC.
Setting up your merchant account this way allows the Bitcoin you send for payment to be circulated back to you when merchant payouts are run.