FIX: Rely on openers.BZ2File to provide correct class

Author: effigies

nibabel/tests/test_volumeutils.py

@@ -46,7 +46,7 @@
                            _dt_min_max,
                            _write_data,
                            )
-from ..openers import Opener
+from ..openers import Opener, BZ2File
 from ..casting import (floor_log2, type_info, OK_FLOATS, shared_range)
 
 from numpy.testing import (assert_array_almost_equal,
@@ -71,7 +71,7 @@ def test__is_compressed_fobj():
     with InTemporaryDirectory():
         for ext, opener, compressed in (('', open, False),
                                         ('.gz', gzip.open, True),
-                                        ('.bz2', bz2.BZ2File, True)):
+                                        ('.bz2', BZ2File, True)):
             fname = 'test.bin' + ext
             for mode in ('wb', 'rb'):
                 fobj = opener(fname, mode)
@@ -94,7 +94,7 @@ def make_array(n, bytes):
     with InTemporaryDirectory():
         for n, opener in itertools.product(
                 (256, 1024, 2560, 25600),
-                (open, gzip.open, bz2.BZ2File)):
+                (open, gzip.open, BZ2File)):
             in_arr = np.arange(n, dtype=dtype)
             # Write array to file
             fobj_w = opener(fname, 'wb')

nibabel/volumeutils.py

@@ -12,7 +12,6 @@
 import sys
 import warnings
 import gzip
-import bz2
 from collections import OrderedDict
 from os.path import exists, splitext
 from operator import mul
@@ -21,7 +20,7 @@
 import numpy as np
 
 from .casting import (shared_range, type_info, OK_FLOATS)
-from .openers import Opener
+from .openers import Opener, BZ2File
 from .deprecated import deprecate_with_version
 from .externals.oset import OrderedSet
 
@@ -40,7 +39,7 @@
 default_compresslevel = 1
 
 #: file-like classes known to hold compressed data
-COMPRESSED_FILE_LIKES = (gzip.GzipFile, bz2.BZ2File)
+COMPRESSED_FILE_LIKES = (gzip.GzipFile, BZ2File)
 
 
 class Recoder(object):