Test discovery fails when using latest version of PyTest

[DonJayamanne]

Previous versions would contain quotes around file names:

<Module 'test_foo.py'>
  <Function 'test_a'>
  <Function 'test_b'>

New version of PyTest doesn't.
Hence the code used to parse the output fails.

[crwilcox]

Temporary workaround, pin pytest<=4.0.0 as it seems 4.1.x brought the change