RFR: 8296284: Update CONTRIBUTING guidelines to state that JUnit 5 is used for tests

[Ambarish Rapte]

On Sat, 14 Jun 2025 11:37:30 GMT, Marius Hanl <mhanl at openjdk.org> wrote:

> As written in the ticket, we might want to clarify that we use `JUnit5` for testing in the `CONTRIBUTING` guidelines.
> 
> This is a first idea of how we could document this and also link to the JUnit page in case contributors are not familiar with the framework (or `JUnit5` in particular). 
> 
> Feedback welcome!

CONTRIBUTING.md line 232:

> 230: * Wildcard imports – for example, `import java.util.*;` – are forbidden and may cause the build to fail. Please attempt to configure your IDE so it doesn't generate wildcard imports. An exception to this rule is that wildcard static imports in test classes are allowed, for example, `import static org.junit.jupiter.api.Assertions.*;`.
> 231: * Don't worry too much about import order. Try not to change it but don't worry about fighting your IDE to stop it from doing so.
> 232: * Tests are written using [JUnit5](https://junit.org/junit5/).

Should we mention about JUnit5 under **Test your changes** ([here](https://github.com/openjdk/jfx/blob/fd30c94893156644c0d803b3e7fd8c9731d65fe6/CONTRIBUTING.md?plain=1#L66)), where we mention that a fix should have associated tests?

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PR Review Comment: https://git.openjdk.org/jfx/pull/1828#discussion_r2149064957