> And then we need tests for all these cases !

1. As described above, `ma.array([1,2], mask=False)` and `ma.array([1,2], mask=[False, False])` are equivalent.
2. The case of differing masks *is* already tested `test_nomask`.

arr1 = np.ma.array([1, 2, 3, 4]) results in a mask=[False, False, False, False]
which compares against
self.arr2 = np.ma.array([1, 3, 2, 4], mask=[False, True, True, False])

Can you identify the cases which I have not tested adequately?