Add ut.

tests/ut/ge/single_op/stream_resource_unittest.cc

@@ -66,6 +66,8 @@ TEST_F(UtestStreamResource, test_build_op) {
   res.op_map_[0].reset(single_op);
   res.dynamic_op_map_[1].reset(dynamic_single_op);
 
+  EXPECT_EQ(res.GetOperator(0), nullptr);
+  EXPECT_EQ(res.GetDynamicOperator(1), nullptr);
   EXPECT_EQ(res.BuildOperator(model_data, &single_op, 0), SUCCESS);
   EXPECT_EQ(res.BuildDynamicOperator(model_data, &dynamic_single_op, 1), SUCCESS);
 }