PHPUnit: Fail on warnings #17
Description
Currently, PHPUnit does not fail when PHP warnings occur1. However, PHP warnings can indicate underlying coding issues that should not be ignored, especially in our codebase.
In Icinga Web, we adjust error reporting early on to convert everything into exceptions, ensuring that no potential problems go unnoticed. In contrast, our library tests do not modify error reporting in the same way, which means warnings may slip through unnoticed and not cause test failures.
To improve overall code quality and consistency, PHPUnit should be configured to fail on PHP warnings.