Merge pull request #699 from effigies/rf/delayed_imports

RF: Avoid import-time loading of nose, mock and nibabel.testing

Author: effigies

nibabel/__init__.py

@@ -34,6 +34,19 @@
 
 For more detailed information see the :ref:`manual`.
 """
+
+
+def setup_test():
+    """ Set numpy print options to "legacy" for new versions of numpy
+
+    If imported into a file, nosetest will run this before any doctests.
+    """
+    import numpy
+    from distutils.version import LooseVersion
+    if LooseVersion(numpy.__version__) >= LooseVersion('1.14'):
+        numpy.set_printoptions(legacy="1.13")
+
+
 # module imports
 from . import analyze as ana
 from . import spm99analyze as spm99
@@ -67,19 +80,19 @@
 from . import mriutils
 from . import streamlines
 from . import viewers
-from .testing import setup_test
 
-# Note test requirement for "mock".  Requirement for "nose" tested by numpy.
-try:
-    import mock
-except ImportError:
+import pkgutil
+
+if not pkgutil.find_loader('mock'):
     def test(*args, **kwargs):
         raise RuntimeError('Need "mock" package for tests')
 else:
     from numpy.testing import Tester
     test = Tester().test
     bench = Tester().bench
-    del mock, Tester
+    del Tester
+
+del pkgutil
 
 from .pkg_info import get_pkg_info as _get_pkg_info
 

nibabel/affines.py

@@ -6,7 +6,7 @@
 import numpy as np
 
 from six.moves import reduce
-from .testing import setup_test  # noqa
+from . import setup_test  # noqa
 
 
 class AffineError(ValueError):

nibabel/casting.py

@@ -8,7 +8,7 @@
 from platform import processor, machine
 
 import numpy as np
-from .testing import setup_test  # noqa
+from . import setup_test  # noqa
 
 
 class CastingError(Exception):

nibabel/nicom/dwiparams.py

@@ -21,7 +21,7 @@
 '''
 import numpy as np
 import numpy.linalg as npl
-from ..testing import setup_test as setup_module  # noqa
+from .. import setup_test as setup_module  # noqa
 
 
 def B2q(B, tol=None):

nibabel/nifti1.py

@@ -27,7 +27,7 @@
 from .spm99analyze import SpmAnalyzeHeader
 from .casting import have_binary128
 from .pydicom_compat import have_dicom, pydicom as pdcm
-from .testing import setup_test  # noqa
+from . import setup_test  # noqa
 
 # nifti1 flat header definition for Analyze-like first 348 bytes
 # first number in comments indicates offset in file header in bytes

nibabel/optpkg.py

@@ -1,16 +1,13 @@
 """ Routines to support optional packages """
+import pkgutil
 from distutils.version import LooseVersion
-
 from six import string_types
+from .tripwire import TripWire
 
-try:
-    import nose
-except ImportError:
-    have_nose = False
-else:
+if pkgutil.find_loader('nose'):
     have_nose = True
-
-from .tripwire import TripWire
+else:
+    have_nose = False
 
 
 def _check_pkg_version(pkg, min_version):
@@ -121,6 +118,7 @@ def optional_package(name, trip_msg=None, min_version=None):
 
     def setup_module():
         if have_nose:
+            import nose
             raise nose.plugins.skip.SkipTest('No %s for these tests'
                                              % name)
     return pkg, False, setup_module

nibabel/quaternions.py

@@ -27,7 +27,7 @@
 
 import math
 import numpy as np
-from .testing import setup_test  # noqa
+from . import setup_test  # noqa
 
 MAX_FLOAT = np.maximum_sctype(np.float)
 FLOAT_EPS = np.finfo(np.float).eps

nibabel/testing/__init__.py

@@ -213,13 +213,3 @@ def assert_arr_dict_equal(dict1, dict2):
     for key, value1 in dict1.items():
         value2 = dict2[key]
         assert_array_equal(value1, value2)
-
-
-def setup_test():
-    """ Set numpy print options to "legacy" for new versions of numpy
-
-    If imported into a file, nosetest will run this before any doctests.
-    """
-    from distutils.version import LooseVersion
-    if LooseVersion(np.__version__) >= LooseVersion('1.14'):
-        np.set_printoptions(legacy="1.13")

nibabel/tests/test_optpkg.py

@@ -38,7 +38,12 @@ def test_basic():
     assert_good('os.path')
     # We never have package _not_a_package
     assert_bad('_not_a_package')
+
+    # setup_module imports nose, so make sure we don't disrupt that
+    orig_import = builtins.__import__
     def raise_Exception(*args, **kwargs):
+        if args[0] == 'nose':
+            return orig_import(*args, **kwargs)
         raise Exception(
             "non ImportError could be thrown by some malfunctioning module "
             "upon import, and optional_package should catch it too")