Merge pull request #282 from matthew-brett/refactor-nibabel-data

MRG: '' from `get_nibabel_data()` when missing

Return empty string from get_nibabel_data() if directory does not exist,
instead of None.

Author: matthew-brett

nibabel/tests/nibabel_data.py

@@ -8,7 +8,7 @@
 
 
 def get_nibabel_data():
-    """ Return path to nibabel-data or None if missing
+    """ Return path to nibabel-data or empty string if missing
 
     First use ``NIBABEL_DATA_DIR`` environment variable.
 
@@ -20,7 +20,7 @@ def get_nibabel_data():
         mod = __import__('nibabel')
         containing_path = dirname(dirname(realpath(mod.__file__)))
         nibabel_data = pjoin(containing_path, 'nibabel-data')
-    return nibabel_data if isdir(nibabel_data) else None
+    return nibabel_data if isdir(nibabel_data) else ''
 
 
 def needs_nibabel_data(subdir = None):
@@ -38,7 +38,7 @@ def needs_nibabel_data(subdir = None):
         Decorator skipping tests if required directory not present
     """
     nibabel_data = get_nibabel_data()
-    if nibabel_data is None:
+    if nibabel_data == '':
         return skipif(True, "Need nibabel-data directory for this test")
     if subdir is None:
         return skipif(False)

nibabel/tests/test_minc2_data.py

@@ -25,9 +25,7 @@
 from nose.tools import assert_equal
 from numpy.testing import (assert_array_equal, assert_almost_equal)
 
-NIBABEL_DATA = get_nibabel_data()
-if NIBABEL_DATA is not None:
-    MINC2_PATH = pjoin(NIBABEL_DATA, 'nitest-minc2')
+MINC2_PATH = pjoin(get_nibabel_data(), 'nitest-minc2')
 
 
 def _make_affine(coses, zooms, starts):

nibabel/tests/test_nibabel_data.py

@@ -25,8 +25,8 @@ def test_get_nibabel_data():
     if isdir(local_data):
         assert_equal(nibd.get_nibabel_data(), local_data)
     else:
-        assert_equal(nibd.get_nibabel_data(), None)
+        assert_equal(nibd.get_nibabel_data(), '')
     nibd.environ['NIBABEL_DATA_DIR'] = 'not_a_path'
-    assert_equal(nibd.get_nibabel_data(), None)
+    assert_equal(nibd.get_nibabel_data(), '')
     nibd.environ['NIBABEL_DATA_DIR'] = MY_DIR
     assert_equal(nibd.get_nibabel_data(), MY_DIR)

nibabel/tests/test_parrec_data.py

@@ -17,8 +17,7 @@
 
 from numpy.testing import assert_almost_equal
 
-NIBABEL_DATA = get_nibabel_data()
-BALLS = None if NIBABEL_DATA is None else pjoin(NIBABEL_DATA, 'nitest-balls1')
+BALLS = pjoin(get_nibabel_data(), 'nitest-balls1')
 
 # Amount by which affine translation differs from NIFTI conversion
 AFF_OFF = [-0.93644031, -0.95572686, 0.03288748]