check that we raise not implemented error for a test.

theano/tensor/nnet/conv.py

@@ -708,7 +708,7 @@ class ConvOp(Op):
             raise NotImplementedError('todo')
 
         if self.dx not in (1, 2) or self.dy not in (1, 2):
-            raise Exception("ERROR: We disable ConvOp.grad now when dx or "\
+            raise NotImplementedError("ERROR: We disable ConvOp.grad now when dx or "\
                     "dy are different from 1 and 2, as there is a bug in it.")
 
         all_shape = self.imshp is not None and self.kshp is not None and \

theano/tensor/nnet/tests/test_conv.py

@@ -204,7 +204,8 @@ class TestConv2D(unittest.TestCase):
         self.validate((3,2,7,5), (5,2,2,3), 'valid', subsample=(2,1))
 
         # Fails as of 2012-04-12
-        self.validate((1,1,6,6), (1,1,3,3), 'valid', subsample=(3,3))
+        self.assertRaises(NotImplementedError, self.validate, (1, 1, 6, 6),
+                          (1, 1, 3, 3), 'valid', subsample=(3, 3))
 
 
     def test_shape_Constant_tensor(self):