Google's documentation states that you should upload a 'draft' APK and add your In-App Products to that - you will then to able to test with your developer and other linked 'test' accounts - that's what it says...
It also says you need to use the 'new' Developer Console to add products for v3 of the billing API - but uploading an APK with the new console instantly publishes it!!! - WTG there Google!!!!!
You cannot unpublish an APK/revert to an earlier one either - the 'live' versions is now the test version - BEWARE of this nonsense!!
So you re-upload the old version to fix that and then try to figure-out how to upload a 'draft' APK. Switching to the old console, you can upload and not 'Activate' an APK - however this doesn't get marked as 'draft' so I'm not sure that's what they mean!?
You can add your In-APp products to that, but running that APK on a device/attempting to purchase anything, results in a message saying the 'current version of this application is not configured for In-App Billing'...
At this point you realise you're going around in circles with a company who's documentation is a lot of nonsense so you resort to this place for help! - please? :)
Someone must have managed to get this to work - would they care to share the EXACT steps for getting a new APK uploaded as 'Draft' with In-App Products which can actually be purchased (for testing purposes) please?
I'm off to swear a lot on the Google forums now :)