I am doing some fairly complex unit tests using PHPUnit. In these tests some files are being generated in temp dirs. After test is finished all this get's wiped. Is there a way to say to framework to leave generated content untouched?
There are 2 ways you could achieve this. Without knowing what exactly clears those files, my best bet is to subclass PHPUnit\Framework\TestCase and implement tearDown or tearDownAfterClass there (and have the relevant test cases subclass that instead), or alternatively by using register_shutdown_function in your bootstrap script.
The tearDown/shutdown method could simply rename the temp dir and mkdir a new one so there'll be nothing to clear, but it's still best to not have those files cleared in the first place. If that code sits inside your vendor/ directory, it's still possible to modify those files.