Disable paratest for a specific testsuite / run all from that test suite on the same single process

[alexander-schranz]

My project have 2 test suites:

    <testsuites>
        <!-- Run Unit Tests before Functional Tests for better Developer Experience -->
        <testsuite name="Project Unit Suite"> <!-- ~ 3500 tests --> <!-- phpunit 2-4 seconds paratest ~20 seconds -->
            <directory>tests/Unit</directory>
        </testsuite>
        
        <testsuite name="Project Functional Suite"> <!-- ~ 2500 tests -->
            <directory>tests/Functional</directory>
        </testsuite>
    </testsuites>

The Unit test are very fast without paratest 2-4 seconds with paratest the Unit tests around 20 seconds so single process is here 5-10x faster.

So maybe there is an option to tell paratest to only split a specific test suite up. So 1 process does the unit test suite and the other test suites are splitted up into the threads like for functional tests like before.

[Slamdunk]

No solution so far, but any PR is welcome.