TEST,STY: Fixes to opener tests, unused import in benchmark.

Author: pauldmccarthy

nibabel/benchmarks/bench_arrayproxy_slicing.py

@@ -15,7 +15,6 @@
 """
 
 from timeit import timeit
-import contextlib
 import gc
 import itertools as it
 import numpy as np

nibabel/tests/test_openers.py

@@ -137,13 +137,13 @@ def test_Opener_gzip_type():
             (False, {'mode' : 'rb', 'keep_open' : 'auto'}, GzipFile),
             (False, {'mode' : 'wb', 'keep_open' : True},   GzipFile),
             (False, {'mode' : 'wb', 'keep_open' : False},  GzipFile),
-            (False, {'mode' : 'rb', 'keep_open' : 'auto'}, GzipFile),
+            (False, {'mode' : 'wb', 'keep_open' : 'auto'}, GzipFile),
             (True,  {'mode' : 'rb', 'keep_open' : True},   MockIndexedGzipFile),
             (True,  {'mode' : 'rb', 'keep_open' : False},  GzipFile),
             (True,  {'mode' : 'rb', 'keep_open' : 'auto'}, MockIndexedGzipFile),
             (True,  {'mode' : 'wb', 'keep_open' : True},   GzipFile),
             (True,  {'mode' : 'wb', 'keep_open' : False},  GzipFile),
-            (True,  {'mode' : 'rb', 'keep_open' : 'auto'}, GzipFile),
+            (True,  {'mode' : 'wb', 'keep_open' : 'auto'}, GzipFile),
         ]
 
         for test in tests: