>Most of the pain was in realizing we didn't have enough UI regression tests. Every 'incident' sparked a new set of tests and over time the incidents stopped ha

>Most of the pain was in realizing we didn't have enough UI regression tests. Every 'incident' sparked a new set of tests and over time the incidents stopped happening. I noticed a process similar to this where bugs from production would appear to 'migrate' from tested scenarios to untested scenarios. We'd start off with UI tests on a browser, for example, and then the bugs would be clamped down on there but would seem now to crop up in API interactions or untested browsers. Then we started accommodating the tests to handle different browsers and mocking API interactions and the bugs would start cropping up somewhere else. What was counterintuitive was that, even though code coverage metrics were really quite low, most bugs cropped up in areas of the code with automated test coverage. "Environmental" coverage seemed to matter much, much more.