added test for unused explicit input in test_copy_delete_updates

theano/compile/tests/test_function_module.py

@@ -383,12 +383,14 @@ class T_function(unittest.TestCase):
             assert cpy(1)[0] == 4
             assert cpy(1)[0] == 4
 
-        # Test if unused implicit inputs from delete_updates are ignored
-        # as intended.
+        # Test if unused implicit and explicit inputs from delete_updates
+        # are ignored as intended.
         for mode in ["FAST_RUN", "FAST_COMPILE"]:
             ori = theano.function([x], x, mode=mode, updates={z: z * 2})
             cpy = ori.copy(delete_updates=True)
 
+            ori = theano.function([x, y], x, mode=mode, updates={z: z + y})
+            cpy = ori.copy(delete_updates=True)
 
     def test_shared_state0(self):
         a = T.scalar()  # the a is for 'anonymous' (un-named).