Steps to reproduce the Unicode bug

gistfile1.sh-session

$ pip install testunicodepackagedependant
Downloading/unpacking testunicodepackagedependant
  Downloading testunicodepackagedependant-1.0.tar.gz
  Storing download in cache at /Users/ambv/.pip/cache/https%3A%2F%2Fpypi.python.org%2Fpackages%2Fsource%2Ft%2Ftestunicodepackagedependant%2Ftestunicodepackagedependant-1.0.tar.gz
  Running setup.py (path:/private/tmp/testestest/build/testunicodepackagedependant/setup.py) egg_info for package testunicodepackagedependant

Downloading/unpacking testunicodepackage==1.0 (from testunicodepackagedependant)
  Downloading testunicodepackage-1.0.tar.gz
Cleaning up...
Exception:
Traceback (most recent call last):
  File "/private/tmp/testestest/lib/python2.7/site-packages/pip/basecommand.py", line 122, in main
    status = self.run(options, args)
  File "/private/tmp/testestest/lib/python2.7/site-packages/pip/commands/install.py", line 278, in run
    requirement_set.prepare_files(finder, force_root_egg_info=self.bundle, bundle=self.bundle)
  File "/private/tmp/testestest/lib/python2.7/site-packages/pip/req.py", line 1197, in prepare_files
    do_download,
  File "/private/tmp/testestest/lib/python2.7/site-packages/pip/req.py", line 1375, in unpack_url
    self.session,
  File "/private/tmp/testestest/lib/python2.7/site-packages/pip/download.py", line 582, in unpack_http_url
    unpack_file(temp_location, location, content_type, link)
  File "/private/tmp/testestest/lib/python2.7/site-packages/pip/util.py", line 625, in unpack_file
    untar_file(filename, location)
  File "/private/tmp/testestest/lib/python2.7/site-packages/pip/util.py", line 556, in untar_file
    path = os.path.join(location, fn)
  File "/private/tmp/testestest/bin/../lib/python2.7/posixpath.py", line 80, in join
    path += '/' + b
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc5 in position 1: ordinal not in range(128)

Storing debug log for failure in /Users/ambv/.pip/pip.log

$ pip install testunicodepackage
Downloading/unpacking testunicodepackage
  Downloading testunicodepackage-1.0.tar.gz
  Storing download in cache at /Users/ambv/.pip/cache/https%3A%2F%2Fpypi.python.org%2Fpackages%2Fsource%2Ft%2Ftestunicodepackage%2Ftestunicodepackage-1.0.tar.gz
  Running setup.py (path:/private/tmp/testestest/build/testunicodepackage/setup.py) egg_info for package testunicodepackage

Installing collected packages: testunicodepackage
  Running setup.py install for testunicodepackage

Successfully installed testunicodepackage
Cleaning up...

$ pip install testunicodepackagedependant
Downloading/unpacking testunicodepackagedependant
  Using download cache from /Users/ambv/.pip/cache/https%3A%2F%2Fpypi.python.org%2Fpackages%2Fsource%2Ft%2Ftestunicodepackagedependant%2Ftestunicodepackagedependant-1.0.tar.gz
  Running setup.py (path:/private/tmp/testestest/build/testunicodepackagedependant/setup.py) egg_info for package testunicodepackagedependant

Requirement already satisfied (use --upgrade to upgrade): testunicodepackage==1.0 in ./lib/python2.7/site-packages (from testunicodepackagedependant)
Installing collected packages: testunicodepackagedependant
  Running setup.py install for testunicodepackagedependant

Successfully installed testunicodepackagedependant
Cleaning up...