Fix test that got broken under Python 2

IPython/utils/warn.py

@@ -1,66 +1,66 b''
 # encoding: utf-8
 """
 Utilities for warnings.  Shoudn't we just use the built in warnings module.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2009  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import sys
 
 from IPython.utils import io
 
 #-----------------------------------------------------------------------------
 # Code
 #-----------------------------------------------------------------------------
 
 def warn(msg,level=2,exit_val=1):
     """Standard warning printer. Gives formatting consistency.
 
     Output is sent to io.stderr (sys.stderr by default).
 
     Options:
 
     -level(2): allows finer control:
       0 -> Do nothing, dummy function.
       1 -> Print message.
       2 -> Print 'WARNING:' + message. (Default level).
       3 -> Print 'ERROR:' + message.
       4 -> Print 'FATAL ERROR:' + message and trigger a sys.exit(exit_val).
 
     -exit_val (1): exit value returned by sys.exit() for a level 4
     warning. Ignored for all other levels."""
 
     if level>0:
         header = ['','','WARNING: ','ERROR: ','FATAL ERROR: ']
-        print >> io.stderr, '%s%s' % (header[level],msg)
+        io.stderr.write('%s%s' % (header[level],msg))
         if level == 4:
             print >> io.stderr,'Exiting.\n'
             sys.exit(exit_val)
 
             
 def info(msg):
     """Equivalent to warn(msg,level=1)."""
 
     warn(msg,level=1)
 
     
 def error(msg):
     """Equivalent to warn(msg,level=3)."""
 
     warn(msg,level=3)
 
     
 def fatal(msg,exit_val=1):
     """Equivalent to warn(msg,exit_val=exit_val,level=4)."""
 
     warn(msg,exit_val=exit_val,level=4)