Some programs, including some test suites, produce no output in case of correct operation, and only produce output in the form of error messages if something has gone wrong.
This makes for nice, non-verbose, tools.
Unfortunately, bugs can also reduce (result?) in code being skipped and no output produced. Therefore, for test suites, it is a good idea to provide TestPositiveConfirmation, i.e. to indicate
I have occasionally used multilayer or folded output formats, to hide details but still make them available.
E.g.