Virtual threads in existing FJP logic

[Christian Stein]

Hi everybody,

Marc and I from the JUnit team are exploring ways how to
integrate virtual threads into the Jupiter test engine. Today
we're using a FJP to enable parallel test execution.

Find the implementation here [0], where at end of the source
file, you'll see our custom ForkJoinWorkerThreadFactory and
the custom ForkJoinWorkerThread implementation.

My idea was to "simply" configure those custom classes to
create virtual threads. Is this possible? If not, we might
resort to add a virtual thread based implementation of the
HierarchicalTestExecutorService interface.

Cheers,
Christian

[0]:
https://github.com/junit-team/junit5/blob/master/junit-platform-engine/src/main/java/org/junit/platform/engine/support/hierarchical/ForkJoinPoolHierarchicalTestExecutorService.java