svn+ssh://pythondev@svn.python.org/python/trunk

........
  r76805 | benjamin.peterson | 2009-12-13 13:19:07 -0600 (Sun, 13 Dec 2009) | 7 lines

  accept None as the same as having passed no argument in file types #7349

  This is for consistency with imitation file objects like StringIO and BytesIO.

  This commit also adds a few tests, where they were lacking for concerned
  methods.
........