Fail build for JUnit discovery issues

[sbrannen]

Overview

JUnit 5.13 introduced support for Discovery Issues which typically indicate configuration errors in tests that may result in unexpected behavior.

Furthermore, discovery issues that are currently reported at INFO level may later be reported at WARNING or ERROR level -- for example, in JUnit 6.

In order to ensure that our test suite does not suffer from such potential errors, we should set the junit.platform.discovery.issue.severity.critical configuration parameter to INFO (instead of leaving it with the default ERROR configuration).

Doing so aligns with our build configuration which fails the build for selected warnings in Java source code and Javadoc.

If we later determine that INFO causes unnecessary issues for us, we can switch to WARNING.

Related Issues

• Discovery issue incorrectly reported for abstract inner class junit-team/junit-framework#4635
• Discovery issue incorrectly reported for abstract @Test method in abstract class junit-team/junit-framework#4636
• Upgrade to JUnit 5.13.2 #35103