We added method DataProvider.entries(), which can be used to pass both the key and the value from array rows. It's useful for using already existing collections, of which their keys should also be passed to the test cases.
Test cases are being called with two arguments, the first being the key from the array, and the other being the value (regardless of the value type).
More features will be coming, in current beta there are: DataProvider.filter(), DataProvider.reindex(), DataProvider.reindexTo(), DataProvider.flatMap() and some others.