title: Pytest init setup for few modules
body: <p>Say i have next tests structure:</p>
  
  <pre>
  test/
    module1/   
      test1.py
    module2/
      test2.py
    module3/
      test3.py
  </pre>
  
  <p>How can i setup some method to be called only once before all this tests?</p>