*I/Ads: Use AdRequest.Builder.addTestDevice(“33BE2250B43518CCDA7DE426D04EE232”) to get test ads on this device. *
In this example test device is 33BE2250B43518CCDA7DE426D04EE232.
If ads were shown fine on test device, it should also working in shipping. Earlier you can check in development build without added test devices. It could be easier to find problems because logs are enabled. Everything is described in User Guide. You shouldn’t do anything more.