Referring more to smaller places like my own - few hundred employees with ~20 person IT team (~10 developers).
I read enough about testing that it seems industry standard. But whenever I talk to coworkers and my EM, it’s generally, “That would be nice, but it’s not practical for our size and the business would allow us to slow down for that.” We have ~5 manual testers, so things aren’t considered “untested”, but issues still frequently slip through. It’s insurance software so at least bugs aren’t killing people, but our quality still freaks me out a bit.
I try to write automated tests for my own code, since it seems valuable, but I avoid it whenever it’s not straightforward. I’ve read books on testing, but they generally feel like either toy examples or far more effort than my company would be willing to spend. Over time I’m wondering if I’m just overly idealistic, and automated testing is more of a FAANG / bigger company thing.
Automated tests are pretty common, yes. It’s not strictly speaking a matter of company size, but moreso company technical maturity.
Automated tests do not slow your business down, it is in fact the only way to not get slowed down as the amount of code you maintain increases.
The alternative cost of not having tests catch issues before they reach production is very significant - an error caught by an automated test costs nothing, while an error that makes it into production can cause immense harm to the business, if only for the time necessary to remediate the issue, which is time that could have been spent on actually making progress on delivering new features.
Not to mention the high cost of having to employ increasing amounts of manual testers just to keep the worst of issues from slipping through.
All in all, not having automated tests in place is a significant mistake from a business perspective. You might want to have a frank discussion with your CTO about it.