Make sure we test urlsplit() / urlunsplit() directly, rather than guessing that urlparse() / urlunparse() use them.
Make sure we test urlsplit() / urlunsplit() directly, rather than
guessing that urlparse() / urlunparse() use them.

Add tests of urldefrag().

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator