Google has commenced the testing of Wear OS 5.1, its upcoming operating system (OS) for Android-based wearables such as smartwatches, according to a report. Test builds of the OS are said to have been spotted for the Pixel Watch 2 which suggests that it may be based on a different version of Android.Google has commenced the testing of Wear OS 5.1, its upcoming operating system (OS) for Android-based wearables such as smartwatches, according to a report. Test builds of the OS are said to have been spotted for the Pixel Watch 2 which suggests that it may be based on a different version of Android.