2to3: Apply `imports` fixer.

The `imports` fixer deals with the standard packages that have been
renamed, removed, or methods that have moved.

cPickle      -- removed, use pickle
commands     -- removed, getoutput, getstatusoutput moved to subprocess
urlparse     -- removed, urlparse moved to urllib.parse
cStringIO    -- removed, use StringIO or io.StringIO
copy_reg     -- renamed copyreg
_winreg      -- renamed winreg
ConfigParser -- renamed configparser
__builtin__  -- renamed builtins

In the case of `cPickle`, it is imported as `pickle` when python < 3 and
performance may be a consideration, but otherwise plain old `pickle` is
used.

Dealing with `StringIO` is a bit tricky. There is an `io.StringIO`
function in the `io` module, available since Python 2.6, but it expects
unicode whereas `StringIO.StringIO` expects ascii. The Python 3
equivalent is then `io.BytesIO`. What I have done here is used BytesIO
for anything that is emulating a file for testing purposes. That is more
explicit than using a redefined StringIO as was done before we dropped
support for Python 2.4 and 2.5.

Closes #3180.

1 files changed, 6 insertions, 2 deletions

diff --git a/numpy/testing/utils.py b/numpy/testing/utils.py
index c08dd0c33..62046814f 100644
--- a/numpy/testing/utils.py
+++ b/numpy/testing/utils.py
@@ -12,6 +12,11 @@ import types
 import warnings
 from .nosetester import import_nose
 
+if sys.version_info[0] >= 3:
+    from io import StringIO
+else:
+    from StringIO import StringIO
+
 __all__ = ['assert_equal', 'assert_almost_equal','assert_approx_equal',
            'assert_array_equal', 'assert_array_less', 'assert_string_equal',
            'assert_array_almost_equal', 'assert_raises', 'build_err_msg',
@@ -346,8 +351,7 @@ def print_assert_equal(test_string,actual,desired):
     import pprint
 
     if not (actual == desired):
-        import cStringIO
-        msg = cStringIO.StringIO()
+        msg = StringIO()
         msg.write(test_string)
         msg.write(' failed\nACTUAL: \n')
         pprint.pprint(actual,msg)