title: pytest python src layout
body: <p>I'm trying out the one of the recommended python package layouts with the src directory. </p>
  
  <p><a href="https://i.stack.imgur.com/RRwPR.png" rel="noreferrer"><img src="https://i.stack.imgur.com/RRwPR.png" alt="enter image description here"></a></p>
  
  <p>My problem is when I run pytest from the command line my tests are not finding my python package.  I tried running from the top level of this directory and within the tests directory but still getting ModuleNotFoundError exception.  I'm running python 3.5 with pytest-3.5.0. </p>
  
  <p>What is the recommend way to execute pytest from this type of python package layout?</p>