Should we migrate to JUnit 5?

[pavelhoral]

I want to start a discussion about potentially migrating to JUnit 5. The main objective of this issue is to enumerate potential flaws of TestNG, benefits of JUnit 5 and any other topics connected with the migration. This issue is not meant to be call to action.

Points worth consideration

• Build system support
  • We are using Maven, both frameworks integrate well with it.
• Code coverage support
  • TODO
• OSGi support
  • Wren:IDM is specific in a way that it is OSGi based project. AFAIK only JUnit has components to help with OSGi testing. Many projects from the OSGi heavily rely on JUnit (e.g. bnd and Apache Slign).
  • TODO what about bnd testing?
• IDE support
  • Eclipse: JUnit is the official test framework for the IDE itself and provides a bit better UX than TestNG
  • IDEA: TODO
• Community support
  • Using GitHub's metrics TestNG has 1.6k stars JUnit has 4.3k stars. Both projects have pretty much the same number of opened issues and are under active development.
• Wren Security support
  • Every Wren Security project is using TestNG right now. Switching JUnit in Wren:IDM would be pretty significant anomaly in that sense.
  • There is no shared library or process that makes the switch unfeasible. New framework would bring additional complexity to the interconnected family of Wren Security project, however Wren:IDM is the odd one out and the switch does not need to have impact on anything else (or maybe we can slowly switch the rest of the platform as well). Switching one project to JUnit is not that big of a deal, considering that this project is also the only OSGi project here.

Why we want to switch

• OSGi support - if we want to write better bundle integration tests
• Eclipse support - see IDE support in previous section
• TODO

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Disclaimer 1: I am pretty sure this is not the right place for this discussion - we can move it later (feel free to suggest better format).
Disclaimer 2: I have much more experience working with JUnit than TestNG... so I am definitely biased.