diff --git a/include/io.h b/include/bus_io.h
similarity index 90%
rename from include/io.h
rename to include/bus_io.h
index 435fd5a..8bac72d 100644
--- a/include/io.h
+++ b/include/bus_io.h
@@ -2,8 +2,8 @@
 // Created by ricardo on 2022/5/6.
 //
 
-#ifndef AUTO_PILOT_BUS_IO_H
-#define AUTO_PILOT_BUS_IO_H
+#ifndef AUTO_PILOT_BUS_BUS_IO_H
+#define AUTO_PILOT_BUS_BUS_IO_H
 #include "rail.h"
 #include "query.h"
 
@@ -49,4 +49,4 @@ read_state_t ReadInput(up_bus_t* up_queries, down_bus_t* down_queries);
  */
 void PrintState(up_bus_t* up_queries, down_bus_t* down_queries, rail_node_t* rails);
 
-#endif //AUTO_PILOT_BUS_IO_H
+#endif //AUTO_PILOT_BUS_BUS_IO_H
diff --git a/include/rail.h b/include/rail.h
index c48f56f..02f237d 100644
--- a/include/rail.h
+++ b/include/rail.h
@@ -38,4 +38,6 @@ extern rail_node_t* rails;
  */
 rail_node_t *FindNode(int id);
 
+int add(int a, int b);
+
 #endif //AUTO_PILOT_BUS_RAIL_H
diff --git a/src/io.c b/src/bus_io.c
similarity index 67%
rename from src/io.c
rename to src/bus_io.c
index 1544ebd..27fb895 100644
--- a/src/io.c
+++ b/src/bus_io.c
@@ -1,4 +1,4 @@
 //
 // Created by ricardo on 2022/5/6.
 //
-#include "io.h"
+#include "bus_io.h"
diff --git a/src/rail.c b/src/rail.c
index e7ebe6f..0dd3efd 100644
--- a/src/rail.c
+++ b/src/rail.c
@@ -1,3 +1,8 @@
 #include "rail.h"
 
-rail_node_t *rails;
\ No newline at end of file
+rail_node_t *rails;
+
+int add(int a, int b)
+{
+    return a+ b;
+}
\ No newline at end of file
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index a81ac16..a142fe9 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -1,6 +1,8 @@
 cmake_minimum_required(VERSION 3.0)
 project(bus_test)
 
+set(CMAKE_CXX_STANDARD 11)
+
 add_subdirectory(./GTest)
 
 include_directories(GTest/googletest/include)
diff --git a/test/io_test.cpp b/test/io_test.cpp
new file mode 100644
index 0000000..77a01a1
--- /dev/null
+++ b/test/io_test.cpp
@@ -0,0 +1,21 @@
+//
+// Created by ricardo on 2022/5/7.
+//
+#include "gtest/gtest.h"
+#include "gmock/gmock.h"
+extern "C"
+{
+#include "rail.h"
+}
+
+using ::testing::Return;
+using ::testing::AtLeast;
+using ::testing::Exactly;
+
+using namespace testing;
+
+TEST(test, test)
+{
+    int result = add(1, 1);
+    EXPECT_EQ(2, result);
+}