Update test_require versions

Author: ashwoods

setup.py

@@ -73,10 +73,10 @@
     'nose',
     'pycodestyle',
     'pytz',
-    'pytest>=3.1.0,<3.2.0',
+    'pytest>=3.2.0,<3.3.0',
     'pytest-timeout==1.2.0',
     'pytest-xdist==1.18.2',
-    'pytest-pythonpath',
+    'pytest-pythonpath==0.7.1',
     'pytest-sugar==0.8',
     'pytest-assume',
     'pytest-cov',