Create a test case for using Eland with a datastream

[sethmlarson]

Currently we don't test (or document) that Eland should work with data streams, we should probably test that everything works properly.

[Winterflower]

I'd be interested in taking a look at this - would be cool to learn more about data streams, too!

[sethmlarson]

@Winterflower That'd be awesome! Let me know if you have questions we can collab