As others have echoed, customers don’t buy code. They buy a tool that is reliable and solves their problem. You could have 100s of tests but server could easil

As others have echoed, customers don’t buy code. They buy a tool that is reliable and solves their problem. You could have 100s of tests but server could easily fall over. So it’s always a trade off. One thing I can say is if you sow the seeds early, it’s easier to add a test with a new feature than add a 100 tests to a 2 year old feature that no one understands and keeps on falling over. Some companies take this to extreme on both ends. Either no tests at all or everything needs 100% coverage delaying time to get things in the hands of customers. Most pragmatic places I have worked at invest in test infra once they have good product market fit. Make it easy to write tests and fast to run and debug them. If it’s easy to do the right thing, why not do it ?