[marcosdumay]

It's blatantly obvious that some of the benefits of extensive testing are covered by a type system. Even by a mostly useless one like Java's.

If you look at any well tested program in a dynamic language, almost all the tests check the same properties that a type system would also check by default. If you remove those, usually only a few remain that test non-trivial properties.

EDIT: And I just love that in the time I took to write this, somebody wrote a comment about how it isn't so. No, it is still blatantly obvious.