Test coverage

[perrygeo]

We need to do more direct unit tests and make sure we're hitting all the code.

[virginiayung]

Per chat with @perrygeo last Friday, I'm going to refactor pansharpen python api (#8) and write unit tests that test specific behaviors of numpy array calculations. A good example of this kind of direct unit testing would be what @dnomadb wrote in test_make_lat_lngs, which tests specifically the creation function for latitude and longitude in rio-toa's test_sun_utils.py.

[virginiayung]

I added more property-based tests in PR #13.

Problems:

1. Tests passed locally and on circleci (Python 2.7.10 and 3.5.0) but coverage data is not being sent to Coverage.py and I got this warning:
   Coverage.py warning: No data was collected..
2. I'm also wondering why it's running on 2.7.6 when I specified pyenv local version to be 2.7.10 in circle.yml

Possible culprit:

I suspect that the problem lies with pytest-cov. Relative paths are confusing coverage when the measured script is run from another directory. Digging into this now.

Running pytest locally with the same flags: py.test --cov pansharpen --cov-report term-missing --ignore=venv

[virginiayung]

My workaround for now is to use versions of Python pre-installed by Circleci on Ubuntu 12.04 and Ubuntu 14.04 build images and run tests on Python 2.7.11 and 3.5.0 separately. Currently our test coverage is 96%

2.7.11 Build

3.5.0 Build

[virginiayung]

🚢 in PR #13. I'm closing this ticket for now. We can revisit tests later!