title: How to tell pytest-xdist to run tests from one folder sequencially and the rest in parallel?
body: <p>Imagine that I have <code>test/unit/...</code> which are safe to run in parallel and <code>test/functional/...</code> which cannot be run in parallel yet.</p>
  
  <p>Is there an easy way to convince pytest to run the <code>functional</code> ones sequentially? Consider that we are talking about a big number of tests so altering each test function/method would be very noisy.</p>
  
  <p>At this moment we run tests with marker filters so mainly we run them separated. Still, I am looking for a solution for removing the need to run them separated.</p>