[Test] add Identity op case to test_remove_identity_ops

tests/transformation/test_remove_identity_ops.py

@@ -51,25 +51,30 @@ def insert_identity_op(model, op, as_first_node, approx):
         val = np.asarray([zero_val], dtype=np.float32)
     elif op in ["Mul", "Div"]:
         val = np.asarray([one_val], dtype=np.float32)
+    elif op in ["Identity"]:
+        val = None
     else:
         return
 
     graph = model.graph
+    if val is None:
+        inplist = ["inp" if as_first_node else "div_out"]
+    else:
+        model.set_initializer("value", val)
+        inplist = ["inp" if as_first_node else "div_out", "value"]
+    identity_node = helper.make_node(op, inplist, ["ident_out"])
     if as_first_node:
-        identity_node = helper.make_node(op, ["inp", "value"], ["ident_out"])
         graph.node.insert(0, identity_node)
         graph.node[1].input[0] = "ident_out"
     else:
-        identity_node = helper.make_node(op, ["div_out", "value"], ["ident_out"])
         graph.node.insert(3, identity_node)
         graph.node[-1].input[0] = "ident_out"
-    model.set_initializer("value", val)
 
     return model
 
 
 # identity operations to be inserted
-@pytest.mark.parametrize("op", ["Add", "Sub", "Mul", "Div"])
+@pytest.mark.parametrize("op", ["Add", "Sub", "Mul", "Div", "Identity"])
 @pytest.mark.parametrize("approx", [False, True])
 @pytest.mark.parametrize("as_first_node", [False, True])
 def test_remove_identity_ops(op, as_first_node, approx):