title: why the doctest didn't work in qpython3
body: <p>I'm trying to use doctest in qpython. But the script didn't work , which it it ok in PC enviroment.</p>
  
  <p>It is just two line different with the my script in PC enviroment:
  import sl4a
  droid = sl4a.Android()</p>
  
  <p>After run the script in qpython, I can see the log of docctest, but the test case seems not be tested. The msg I got is :
  11 items had no tests:
  ...
  0 tests in 11 items.
  0 passed and 0 faied.
  Test passed</p>
  
  <p>Is there any important things I missed?
  Thanks for your help!</p>