Test code is packaged but not the data required to run the tests

[fabianegli]

Either the data should be packaged, too, or the tests omitted from the package.

The current test datasets are about 3.7 MB which would add roughly 12% to the total package size which is ~30 MB. I think that would be OK.

👍 for including the test data in the package
👎 for not packaging the tests