make nilearn optional

Author: Shoshana Berleant

nipype/algorithms/stats.py

@@ -16,7 +16,6 @@
 from builtins import str
 
 import numpy as np
-import nilearn.input_data as nl
 
 from .. import logging
 from ..interfaces.base import (traits, TraitedSpec, BaseInterface,
@@ -67,6 +66,8 @@ class SignalExtraction(BaseInterface):
     output_spec = SignalExtractionOutputSpec
 
     def _run_interface(self, runtime):
+        import nilearn.input_data as nl
+
         ins = self.inputs
 
         if ins.stat == 'mean': # always true for now

nipype/algorithms/tests/test_stats.py

@@ -7,9 +7,17 @@
 
 import numpy as np
 
-from ...testing import (assert_equal, utils, assert_almost_equal, raises)
+from ...testing import (assert_equal, utils, assert_almost_equal, raises,
+                        skipif)
 from .. import stats
 
+no_nilearn = True
+try:
+    import nilearn
+    no_nilearn = False
+except ImportError:
+    pass
+
 class TestSignalExtraction(unittest.TestCase):
 
     filenames = {
@@ -26,6 +34,7 @@ def setUp(self):
         utils.save_toy_nii(self.fake_fmri_data, self.filenames['in_file'])
         utils.save_toy_nii(self.fake_label_data, self.filenames['label_file'])
 
+    @skipif(no_nilearn)
     def test_signal_extraction(self):
         # setup
         wanted = [[-2.33333, 2, .5],
@@ -53,6 +62,7 @@ def test_signal_extraction(self):
                 for j, segment in enumerate(time):
                     assert_almost_equal(segment, wanted[i][j], decimal=1)
 
+    @skipif(no_nilearn)
     @raises(ValueError)
     def test_signal_extraction_bad_class_labels(self):
         # run

requirements.txt

@@ -12,5 +12,3 @@ xvfbwrapper
 psutil
 funcsigs
 configparser
-nilearn
-sklearn