As any other model, this doesn’t say this should fit to every company, but this is the typical idea and what Google follows. You can follow this, but you need to be aware that maybe this is not the best model for your company. This pyramid shows how much of each type of tests you should focus more. […]

https://azevedorafaela.wordpress.com/2016/12/19/evolution-of-business-and-engineering-productivity-gtalk-2016/