Running tests in parallel?

Greetings.

Pardon me to ask: Am I right that most of the Use Cases tests are
executed serially (only)?
Executing the tests seem to take surprisingly long time (8+ minutes?!)
at almost no load on my cpu cores.

If my observation was right: Is that intentional and why would we not
run the tests in parallel?
With my limited understanding, most of the tests create a workbook and
sheets and cells and do something and the assert. I think this could be
done in parallel, unless multiple tests accessed the same workbook?

(I am new to apache projects and I am no developer,  so please go soft
on me.)

Cheers
Andreas