added basic catmath tests

[ghost]

following the 2016 tutorial

[coveralls]

Coverage increased (+1.1%) to 37.931% when pulling 262725d on hackscribble:tutorial_wip into d5fd52c on keeppythonweird:master.

[bobcatfish]

Writing /tmp/easy_install-wey1c_4g/pytest-4.4.1/setup.cfg
Running pytest-4.4.1/setup.py -q bdist_egg --dist-dir /tmp/easy_install-wey1c_4g/pytest-4.4.1/egg-dist-tmp-50mz25gi
/opt/python/3.4.6/lib/python3.4/distutils/dist.py:260: UserWarning: Unknown distribution option: 'project_urls'
  warnings.warn(msg)
/opt/python/3.4.6/lib/python3.4/distutils/dist.py:260: UserWarning: Unknown distribution option: 'long_description_content_type'
  warnings.warn(msg)
warning: no previously-included files found matching 'pyproject.toml'

oh no, looks like our project may have finally fallen behind @mtomwing ... 😅