The scale at Google is unimaginable. For instance, one of their most popular product Gmail has 200+ million users so any change they make, whether big or small, is instantly made available to all these users.
The updates are silently applied in the backend and the average user is often unaware that the cloud software they use all day has been silently patched but the reception is quite different if something breaks or doesn’t work as expected.
If you are curious to know how testing happens at Google, this upcoming title on Amazon - How Google Tests Software – might be of interest. The Test Engineering team have teamed up to share how Google tests cloud software, the best practices for managing code reviews, tracking bugs and everything else that will help improve your testing process.