Google has made IAB testing much simpler and when I'm testing a monthly subscription runs for 5 minutes and then I got the mail from Play Store:
Your ... subscription from ... on Google Play has been cancelled.
But when query inventory / purchase over Play Store API, I still get
"purchaseState":0
Which means "OK". I have been waiting for a day - may be it does not work immediately - but it's still stuck at 0 / OK. Am I doing something wrong?