Add test for shapefile input

[pjsier]

Currently there are test for every input format except for shapefiles, partially because it involves multiple files.

We can create a test here by converting one of the files in the fixtures directory into shapefile format and using that to create a test similar to the GeoJSON test. Converting the GeoJSON file would probably be easiest. The conversion will result in multiple files that should all be included in the fixtures directory

mapshaper is one tool that might be helpful in converting GeoJSON to shapefiles

[niwa-s]

May I work on it?

[pjsier]

@niwa-s sure! Assigning you now. Feel free to post any questions here