Google Cloud Test lab basically runs an automated tests in accordance with your app's targeting criteria on several devices.
Cloud Test Lab can run instrumentation tests that you write using Espresso or Robotium. You can also use the Cloud Test Lab Robo Test to simulate user actions and find crashes in your app.
Clout Test Lab enables the user to run the tests during the development stages via Android Studio and Command line. You can also upload the apk to the developer console and run a robo test or the user written instrumentation test on wide range of devices.
The test results can be found in the developer console under particular project.
The pricing details are yet be announced by Google.