removed test enforcing specific traversal behavior when an op returns

theano/tests/test_gradient.py

@@ -131,38 +131,11 @@ class test_grad_sources_inputs(unittest.TestCase):
                 outputs = [theano.tensor.matrix(),theano.tensor.matrix()]
                 return gof.Apply(self, inputs, outputs)
             def grad(self, inputs, g_out):
-                return [1]
+                return [one]
         i = theano.tensor.matrix()
         a1 = O(self).make_node(i)
         g = grad_sources_inputs([(a1.outputs[0], one)], None, warn_type=False)
-        self.assertTrue(g[i] is 1)
-
-    def test_some_None_igrads(self):
-        """Test that traversal works properly when an op return some None"""
-        class O(gof.op.Op):
-            def __init__(self, tst, grad_ok):
-                self.tst = tst
-                self.grad_ok = grad_ok
-            def make_node(self, *inputs):
-                outputs = [theano.tensor.matrix(),theano.tensor.matrix()]
-                return gof.Apply(self, inputs, outputs)
-            def grad(self, inputs, g_out):
-                if not self.grad_ok:
-                    self.tst.fail()
-                else:
-                    return [1, None]
-        i = theano.tensor.matrix()
-        j = theano.tensor.matrix()
-        k = theano.tensor.matrix()
-        a1 = O(self, True).make_node(i,j)
-        a2 = O(self, True).make_node(a1.outputs[1], k)
-        g = grad_sources_inputs([(a2.outputs[0], one)], None, warn_type=False)
-        self.assertTrue(g[i] is 1 and j not in g and k not in g)
-
-        a1 = O(self, True).make_node(i,j)
-        a2 = O(self, True).make_node(k, a1.outputs[1])
-        g = _grad_sources_inputs([(a2.outputs[0], one)], None)
-        self.assertTrue(g[k] is 1 and i not in g and j not in g)
+        self.assertTrue(g[i] is one)
 
     def test_inputs(self):
         """Test that passing inputs shortens the traversal"""