Make knownfailureif Pytest-compatible

IPython/external/decorators/_decorators.py

@@ -133,9 +133,16 b' def knownfailureif(fail_condition, msg=None):'
         # import time overhead at actual test-time.
         import nose
 
+        try:
+            from pytest import xfail
+        except ImportError:
+
+            def xfail():
+                raise KnownFailureTest(msg)
+
         def knownfailer(*args, **kwargs):
             if fail_condition:
-                raise KnownFailureTest(msg)
+                xfail(msg)
             else:
                 return f(*args, **kwargs)
         return nose.tools.make_decorator(f)(knownfailer)

IPython/external/decorators/_numpy_testing_noseclasses.py

@@ -7,9 +7,15 b' import os'
 
 from nose.plugins.errorclass import ErrorClass, ErrorClassPlugin
 
-class KnownFailureTest(Exception):
-    '''Raise this exception to mark a test as a known failing test.'''
-    pass
+
+try:
+    import pytest
+
+    KnownFailureTest = pytest.xfail.Exception
+except ImportError:
+
+    class KnownFailureTest(Exception):
+        """Raise this exception to mark a test as a known failing test."""
 
 
 class KnownFailure(ErrorClassPlugin):