Rather than deleting the isinstance() check from the tests completely, I
suggest changing it to be:

self.assert_(isinstance(vi[:], tuple))

Also, comparing directly with a tuple is also a fairly common use of
version_info so it would be worth adding a test to explicitly guarantee
that comparison:

self.assert_(vi > (1,0,0))

Patch applied and built cleanly for me, but I haven't checked the doc
build yet.