Adding python 3 to travis

[sdcooke]

No description provided.

[kevinbarabash]

@sdcooke the tests are failing b/c of a missing import:

======================================================================
ERROR: evaluator_test (unittest.loader.ModuleImportFailure)
----------------------------------------------------------------------
ImportError: Failed to import test module: evaluator_test
Traceback (most recent call last):
  File "/opt/python/2.7.14/lib/python2.7/unittest/loader.py", line 254, in _find_tests
    module = self._get_module_from_name(name)
  File "/opt/python/2.7.14/lib/python2.7/unittest/loader.py", line 232, in _get_module_from_name
    __import__(name)
  File "/home/travis/build/Khan/tinyquery/tinyquery/evaluator_test.py", line 11, in <module>
    from tinyquery import context
  File "/home/travis/build/Khan/tinyquery/tinyquery/tinyquery.py", line 7, in <module>
    from tinyquery import compiler
ImportError: cannot import name compiler

The tests are run on travis-ci using the following command:

python -m unittest discover -s tinyquery -p "*_test.py"

I'm not very familiar with running python tests. How are you running the tests locally?

[sdcooke]

Ah I wasn't using the -s - I'm not surprised that fails, because it is confusing the package with the file. I think you'd have to run the tests without the -s to make this work, I don't think there's another way around it:

python -m unittest discover -p "*_test.py"

[kevinbarabash]

@sdcooke cool, that did the trick.

[csilvers]

Thanks for taking care of this @kevinbarabash !