Level 39
Don't understand your question, parallel is not serial :-) , errors seem to be normal, see following doc
https://laravel.com/docs/8.x/testing#parallel-testing-and-databases
That there is also this in the doc
https://laravel.com/docs/8.x/testing#parallel-testing-hooks
I never used it, it seems to be useful to synchronize // tests and that's maybe what you are looking for?