This happens when running test from root directory. Following patch can
workaround this, but this code is there because it is needed, isn't it?
(Related to #4710?)

Index: Lib/zipfile.py
===================================================================
--- Lib/zipfile.py	(revision 71184)
+++ Lib/zipfile.py	(working copy)
@@ -957,11 +957,6 @@
         """Extract the ZipInfo object 'member' to a physical
            file on the path targetpath.
         """
-        # build the destination pathname, replacing
-        # forward slashes to platform specific separators.
-        if targetpath[-1:] in (os.path.sep, os.path.altsep):
-            targetpath = targetpath[:-1]
-
         # don't include leading "/" from file name if present
         if member.filename[0] == '/':
             targetpath = os.path.join(targetpath, member.filename[1:])


When targetpath is "C:/", targetpath becomes "C:" and os.path.join("C:",
"foo") returns "C:foo" instead of "C:/foo"