how much of these tests did you change? I don't like ANY tests where you have to use equalContets/assertEqual

I get for a numpy arrange out put that is ok (e.g. ``unique``). but if the output is a Series (e.g. with value_counts), I don't think that should used at all. I know this is waht the original test did, but value_counts here is a series.) Can you go thru tests and change as much as possible to assert_series_equal?

In the cases of a numpy array is returned use ``self.assert_numpy_array_equal``. The problem with checking contents and equal is it can mask issues with the ordering and/or return types.