title: Python 3 chokes on CP-1252/ANSI reading
body: <p>I'm working on a series of parsers where I get a bunch of tracebacks from my unit tests like:</p>
  
  <pre><code>  File "c:\Python31\lib\encodings\cp1252.py", line 23, in decode
      return codecs.charmap_decode(input,self.errors,decoding_table)[0]
  UnicodeDecodeError: 'charmap' codec can't decode byte 0x81 in position 112: character maps to &lt;undefined&gt;
  </code></pre>
  
  <p>The files are opened with open() with no extra arguemnts.  Can I pass extra arguments to open() or use something in the codec module to open these differently?</p>
  
  <p>This came up with code that was written in Python 2 and converted to 3 with the 2to3 tool.</p>
  
  <p>UPDATE: it turns out this is a result of feeding a zipfile into the parser.  The unit test actually expects this to happen.  The parser should recognize it as something that can't be parsed.  So, I need to change my exception handling.  In the process of doing that now.</p>