How to test the update functions?

[choldgraf]

How can we test the update_ functions in a reliable way? Because since can only specify a start date, not an end date, this makes it kinda tricky to expect the same behavior. What if we chose a high-volume repository like scikit-learn, and used update_XXX for the last 5 days of data. That shouldn't take too long to pull, and we should always get some activity across each of the categories, no?