Status Quo

Using JUnit 5 annotations and mechanisms one can do a lot of things that are syntactically possible but don't make sense. For example, one can annotate a method with both @Test and @BeforeEach.

Proposal

Introduce a mechanism where JUnit itself but also other parties can register rules that will be checked during discovery time, e.g.:

• AmbiguousAnnotationsRule
• DuplicateExtensionsRule
• ProhibitNestedTestsRule (in case a project wants to forbid this style of testing)

Those rules should be listable and configurable from the launcher API: Error, Warning, Off

Rules could work on different level, e.g whole test plan, engine, package, class, method, etc.

Related Issues

• Introduce error handling mechanism for validation and discovery errors #242