title: Do Paypal recurring payments have unique txn_ids?
body: <p>I'm using the Paypal "Subscription" button.  I have an IPN handler and overall I think I've got it all figured out.  My last problem is that apparently there's no good way to test a recurring payment (except to wait for the cycle to occur).  This issue is discussed here: [question]: <a href="https://stackoverflow.com/questions/1364360/testing-paypal-subscription-ipn">Testing Paypal subscription IPN</a></p>
  
  <p>I don't really <em>need</em> to test this recurring payment but I do need to know if every recurring payment will have it's own <strong>txn_id</strong> or if every payment in a subscription shares the same ID.  </p>
  
  <p>Thanks!</p>