Recommend exposing TESTS dict or similar

[bdpedigo]

sklearn exposes a dictionary mapping valid strings for something like a pairwise distance ["euclidean", "l1", etc.] to the corresponding function. Makes it super easy to test if something is a valid key, and get all available options if you are exploring. See here.

Could be useful to have for hyppo too, basically would expose this as a dictionary called TESTS* or something similar.

*note, IMO might be more confusing to call this INDEPENDENCE_TESTS because they can also be used for k-sample, but that's just my opinion

[sampan501]

yep! Currently working on this