How internal tester can download the "Android" pre-released App build?

Could anyone plz let me know, How internal tester can download the "Android" pre-released App build ? Because now "TestFlight" is only for iOS as acquired by Apple. Whether, solution is to upload the Android pre-release app build on "Google Play" and invite internal-tester to get download. **Earlier I used "TestFlight", I downloaded pre-released app build on iOS7 device, the distributed by Developer for internal testing. Thanks,