As per suggestion I'm splitting How do I create a closed beta on the App Store? up.
Can I upload the game I'm developing to Google Play as a closed beta, so I could generate a couple of keys/tokens for my testers? I'm hoping to only publish the game for the public after I'm happy with the game as it's offered on Google Play, as a complete user experience which includes the installation process.
If this is not the usual workflow, how should I do it?