title: How are unique registration id's for GCM for each device generated?
body: <p>I have to test my app for <code>GCM</code> multicast on emulators around 10 or more in number. For this I need to create 10 emulators that can provide me unique registration ids.</p>
  
  <p>I tried cloning a single emulator with a <strong>google account</strong> and loading the userdata-qemu.img into new emulator. In this case the registration ids returned by the new emulator is same as the old one.</p>
  
  <p>I tested the app on two separately created emulators with the same google account in which case they 
  return different registration ids. Certainly <code>GCM</code> does not use account information for that.</p>
  
  <p>I understand that registration id for <code>GCM</code> is generated from the "<strong>app package and device</strong>".
  How does Google uniquely identify a device or emulator instance.</p>
  
  <p>Also tried changing the uuid of the emulator provided in the emulator-user.ini file but of no use. </p>
  
  <p>Certainly I can go about doing this manually , but it would be too cumbersome each time.</p>
  
  <p>Any help would be appreciated.</p>
  
  <p>Thanks</p>