py.test existing status 1; try using python -m pytest instead.

It's only failing for the non 2.x case under nightly (3.12), but this
change should have been made a while ago anyway. Also print
out the python version as part of the run.

Author: rouilj

.travis.yml

@@ -162,8 +162,9 @@ before_script:
 script:
   - PATH=$VIRTUAL_ENV/bin:$PATH
   - export LD_LIBRARY_PATH=$VIRTUAL_ENV/lib:$LD_LIBRARY_PATH
+  - python -c "import sys; print('python version: ', sys.version)"
   - if [[ "$TRAVIS_PYTHON_VERSION" != "2."* ]]; then
-    py.test -r a
+    python -m pytest -r a
       --durations=20
       -W default
       -W "ignore:SelectableGroups:DeprecationWarning" 
@@ -174,7 +175,7 @@ script:
       -v --maxfail=5 test/ --cov=roundup;
     fi
   - if [[ "$TRAVIS_PYTHON_VERSION" == "2."* ]]; then
-      py.test -v -r a --maxfail=5 test/ --cov=roundup;
+      python -m pytest -v -r a --maxfail=5 test/ --cov=roundup;
     fi
   - ./setup.py build_doc