Yes, more or less. The sandbox mode is for iOS. On Android you need to do some different steps.
If you disable the sandbox mode and you sign the apk and upload it to the store as beta, then you can add testers to the project and you can buy the items (without paying, of course) and check if you have configured your project in the right way.
This is the right way of testing in Android. Then, you should be able to get all the responses.