small upgrade following code review.

theano/tensor/basic.py

@@ -1221,12 +1221,13 @@ class _tensor_py_operators:
     T = property(lambda self: transpose(self))
     shape = property(lambda self: shape(self))
     size = property(lambda self: prod(self.shape))
+
     def __len__(self):
-        # We can't implement __len__ as python request that this
-        # function return an integer >=0
-        raise RuntimeError("Theano Variable can't work with len(Theano"
-                           " Variable) due to python restriction. You can use"
-                           " TheanoVariable.shape[0] instead.")
+        # We can't implement __len__ as Python requests that this
+        # function returns an integer >=0
+        raise TypeError("Theano Variables can't work with len(Theano "
+                        "Variable) due to Python restriction. You can use "
+                        "TheanoVariable.shape[0] instead.")
 
     def reshape(self, shape, ndim=None):
         """Return a reshaped view/copy of this variable.

theano/tensor/tests/test_basic.py

@@ -5191,13 +5191,12 @@ class test_broadcast(unittest.TestCase):
 
 
 def test_len():
-    for shape in [(5,), (3, 4), (7, 4, 6), (3, 4, 5)]:
-        val = numpy.random.rand(*shape).astype(config.floatX)
+    for shape in [(5,), (3, 4), (7, 4, 6)]:
         x = tensor.tensor(dtype='floatX', broadcastable=(False,)*len(shape))
         try:
             len(x)
             assert False, "Expected an error"
-        except RuntimeError:
+        except TypeError:
             pass