How many tests do you have? More tests is better. For a 3-year old product the number should be around 10k. How many of them red? If tests are red - it's bad.

How many tests do you have? More tests is better. For a 3-year old product the number should be around 10k. How many of them red? If tests are red - it's bad. For how long they are red? If there is a need to "fix approximately hundred tests", it's a bad sign. I found that amount of tests, tests execution time, test coverage is very important and it answers almost all the questions. How often did you need to sacrifice test coverage to deliver the software? There is always a need to release, there is always deadline. It depends how company react. For example, during Rails 5 release they don't care, just push deadline. It's a good sign, because folks understand that code quality == developer happiness.