title: How do I test my Google Wallet integration when I can't "purchase from myself" in sandbox?
body: <p>I'm integrating google wallet with a php-game. I've come to the part where I want to test if my postback-script does it's job, but I can't seem to find any information on how to make a test purchase. I get this error when I try:</p>
  <p><a href="https://i.stack.imgur.com/TXnvp.png" rel="noreferrer"><img src="https://i.stack.imgur.com/TXnvp.png" alt="" /></a></p>
  
  <p>I'm in the sandbox so I don't understand why this is happening. Help?</p>