Ideally, software tests of a project reliably test all functionality. The mantra should be that software that passes the tests is ready for production usage. This is of course a goal to strive for, for example by continuous improvement.

Using Continuous Delivery and especially Continuous Deployment requires a reliable and sufficient test harness. The software tests are the ultimate quality barrier before production deployment.

Reliable tests that pass should not require any further interaction. Therefore, they should not output verbose logs if the overall execution was successful. While a detailed explanation of what happened during execution is very helpful in failing tests, it becomes distracting in passing runs.