This is needed to include the data files, right? Are there more data files than the ones in ordination? If so, I'd consider directly hard coding them in `package_data` for now. (We should already be shipping tests as they have an `__init__` file).

I would defer a more complex solution until we are expecting to ship more than a few folders of test data. BTW, a package that ships a lot of data is [astropy](https://github.com/astropy/astropy/search?p=1&q=get_package_data&ref=cmdform). They chose to define a `get_package_data` function in each module. But it needs some scaffolding and it's too complex for the current problem.