After running 355 phpunit tests, the next one takes a very long time, why?

Question

PHP

Switched from ubuntu to MacBook (respectively to macOS).
On Ubuntu 1500, phpunit tests ran quickly, and after I moved the project to a poppy, the tests began to run super long.
If you run one test, then it will run quickly, and if you run all the tests, then the first 355 will run quickly and all the rest will be very long (up to 10 minutes one test).
Has anyone encountered this? Maybe I misconfigured something?

Answer 1

- I have something knocking under the hood, sometimes there is a rattle - what could it be?
- This means that something is knocking under your hood, sometimes it rattles.

Options - a lot.
If all the software (versions, settings) match, the question remains about the hardware.
If ubuntu worked with 32 gigs of memory on a terabyte SSD, and the poppy has 8/256, of which 90% are occupied - indeed, why does it suddenly slow down? I'm exaggerating, of course, but nonetheless...
In general, the sign "the first 355 will be executed quickly and all the rest for a very long time" most of all hints at some kind of cache exhaustion. Is this so, and if so, where exactly did the dog rummage - it is already necessary to look specifically at the tests themselves.
According to the data given in the question, there can be only one answer: "The reason is anything."