Support JUnit 6.x testing framework via aligned module

[cleankod]

The JUnit 6.0 release introduces a unified versioning approach:

all modules of JUnit Platform, Jupiter, and Vintage now use the same version number: 6.0.0.

source - JUnit 6.x upgrade guide

As ArchUnit’s archunit-junit5 module is built against JUnit 5.x and Platform 1.x, it cannot be used in environments which adopt JUnit 6.x (Platform 6.x + Jupiter 6.x). This creates a blocker for testing strategies in modern Java projects.

Request

• Introduce a module (e.g., archunit-junit6) targeting JUnit 6.x compatibility.
• Alternatively upgrade archunit-junit5 to detect/enable JUnit 6 support when Platform 6.x and Jupiter 6.x are on the classpath.
• Handle any JUnit 6 API changes (e.g., removed modules, null‐safety annotations) as noted in the JUnit upgrade guide.

Goal

Allow teams using ArchUnit for architectural tests to migrate to JUnit 6.x without compromising dependency alignment or test stability.

[mpkorstanje]

As ArchUnit’s archunit-junit5 module is built against JUnit 5.x and Platform 1.x, it cannot be used in environments which adopt JUnit 6.x (Platform 6.x + Jupiter 6.x). This creates a blocker for testing strategies in modern Java projects.

JUnit 6.0.1 is mostly backwards compatible with JUnit 5.14.1 and JUnit Platform 1.14.1.

You should clarify what those issues are and if you are using the JUnit BOM as recommended by the user guide:

• https://docs.junit.org/current/user-guide/#running-tests-build-gradle-bom
• https://docs.junit.org/current/user-guide/#running-tests-build-maven-bom

[hankem]

JUnit 6.0.1 is mostly backwards compatible with JUnit 5.14.1 and JUnit Platform 1.14.1.

ArchUnit is currently compatible with Java 8, but JUnit 6 requries Java 17.

[mpkorstanje]

I'm under the assumption that @cleankod is trying to use JUnit 6 on Java 17+ with Archunit. 😉

[arukiidou]

I created a small proof‑of‑concept, and it seems to work well.
Would it be okay to move forward with this?

• add support JUnit 6.x testing framework. #1587

Also, is there anything needed to complete this?