nose's assert_raises and mock's patch don't play together well; future's raise_from requires exceptions to be imported without a qualifier

Author: Shoshana Berleant

nipype/testing/tests/test_utils.py

@@ -23,8 +23,21 @@ def test_tempfatfs():
 @patch('subprocess.check_call', MagicMock(
     side_effect=subprocess.CalledProcessError('','')))
 def test_tempfatfs_calledprocesserror():
-    yield assert_raises, IOError, TempFATFS
+    try:
+        TempFATFS()
+    except IOError as e:
+        assert_true(isinstance(e, IOError))
+        assert_true(isinstance(e.__cause__, subprocess.CalledProcessError))
+    else:
+        assert_true(False)
 
+@patch('subprocess.check_call', MagicMock())
 @patch('subprocess.Popen', MagicMock(side_effect=OSError()))
 def test_tempfatfs_oserror():
-    yield assert_raises, IOError, TempFATFS
+    try:
+        TempFATFS()
+    except IOError as e:
+        assert_true(isinstance(e, IOError))
+        assert_true(isinstance(e.__cause__, OSError))
+    else:
+        assert_true(False)

nipype/testing/utils.py

@@ -9,6 +9,7 @@
 import shutil
 import signal
 import subprocess
+from subprocess import CalledProcessError
 from tempfile import mkdtemp
 from ..utils.misc import package_check
 from nose import SkipTest
@@ -62,7 +63,7 @@ def __init__(self, size_in_mbytes=8, delay=0.5):
         try:
             subprocess.check_call(args=mkfs_args, stdout=self.dev_null,
                                   stderr=self.dev_null)
-        except subprocess.CalledProcessError as e:
+        except CalledProcessError as e:
             raise_from(IOError("mkfs.vfat failed"), e)
 
         try: