title: Printing test execution times and pinning down slow tests with py.test
body: <p>I am running unit tests on a CI server using py.test. Tests use external resources fetched over network. Sometimes test runner takes too long, causing test runner to be aborted. I cannot repeat the issues locally.</p>
  
  <p>Is there a way to make py.test print out execution times of (slow) test, so pinning down problematic tests become easier?</p>