Use FileNotFoundError. Implement in py3k for Python 2 compatibility.

Author: arokem

nibabel/loadsave.py

@@ -18,7 +18,7 @@
 from .filebasedimages import ImageFileError
 from .imageclasses import all_image_classes
 from .arrayproxy import is_proxy
-
+from .py3k import FileNotFoundError
 
 def load(filename, **kwargs):
     ''' Load file given filename, guessing at file type
@@ -36,7 +36,7 @@ def load(filename, **kwargs):
        Image of guessed type
     '''
     if not op.exists(filename):
-        raise IOError("No such file: '%s'" % filename)
+        raise FileNotFoundError("No such file: '%s'" % filename)
     sniff = None
     for image_klass in all_image_classes:
         is_valid, sniff = image_klass.path_maybe_image(filename, sniff)

nibabel/py3k.py

@@ -40,6 +40,7 @@ def open_latin1(filename, mode='r'):
     strchar = 'U'
     ints2bytes = lambda seq: bytes(seq)
     ZEROB = bytes([0])
+    FileNotFoundError = FileNotFoundError
 else:
     import StringIO
     StringIO = BytesIO = StringIO.StringIO
@@ -62,6 +63,8 @@ def open_latin1(filename, mode='r'):
     ints2bytes = lambda seq: ''.join(chr(i) for i in seq)
     ZEROB = chr(0)
 
+    class FileNotFoundError(IOError):
+        pass
 
 def getexception():
     return sys.exc_info()[1]

nibabel/tests/test_loadsave.py

@@ -22,6 +22,7 @@
 
 from nose.tools import (assert_true, assert_false, assert_raises,
                         assert_equal, assert_not_equal)
+from ..py3k import FileNotFoundError
 
 data_path = pjoin(dirname(__file__), 'data')
 
@@ -54,7 +55,7 @@ def test_read_img_data():
 
 
 def test_file_not_found():
-    assert_raises(IOError, load, 'does_not_exist.nii.gz')
+    assert_raises(FileNotFoundError, load, 'does_not_exist.nii.gz')
 
 
 def test_read_img_data_nifti():