Phpunit 10 compatibility?

[rutgerrademaker]

Since phpunit 10 got released last week we have received some reports on tests not being executed or failing
As the testing-suite only requires an @stable version, it is up to the package/project to dictate which version of phpunit it really needs.
For that reason I think we do NOT have to update our dependencies.

I post this message mainly to give some clarity/guidance to end-users of the testing-suite

E.g, if you require testing-suite, without restricting phpunit/phpunit to a given version (e.g ^9) it will install version 10 (if you're on php 8.1).

Phpunit states, there is no real reason to update to 10 directly
So, for that reason you might need/want to restrict phpunit/phpunit to e.g ^9 in your project until you are ready to update to version 10

See also https://phpunit.de/announcements/phpunit-10.html

OMGWTFBBQ? I must upgrade to PHPUnit 10 immediately!

No, you do not.

Just because PHPUnit 10 has been released today does not mean that PHPUnit 8 or PHPUnit 9 will no longer work. While old versions of PHPUnit will eventually stop receiving bug fixes, [we will keep them compatible with new versions of PHP for as long as possible](https://phpunit.de/supported-versions.html).

We sincerely hope that you do not use the [Death Star Version Constraint](https://thephp.cc/articles/the-death-star-version-constraint) and therefore do not automatically and unintentionally upgrade to a new major version of PHPUnit.

[Anve94]

I think the actions are also affected by this.
Would be good if this is being picked up we also look into refactoring the tests in general and include it with the scope to get github actions in a stable place

[Anve94]

Assigned this to myself due to work being done on version 3 of the testing suite that would already resolve this.

The new version will change how the dependency is handled and remove it as an inner dependency. We will use the youwe/dependency-installer to install phpunit upstream instead, while still honoring already installed versions upstream.

The testing suite shouldn't be concerned which PHPUnit is installed upstream (just that any is installed for the testing suite to work), and leave it to the composer version constraint checks upstream. The only edge case is upstream having no phpunit dependency and no test cases, in which case it can just install any stable version for these projects.