diff --git a/cii/CMakeLists.txt b/cii/CMakeLists.txt
index 5503ccb2..de64e12f 100644
--- a/cii/CMakeLists.txt
+++ b/cii/CMakeLists.txt
@@ -31,15 +31,15 @@ target_include_directories(cii_static
     )
 
 add_executable(mem_test
-    src/mem_test.c
-    src/mem_test.h
+    tests/mem_test.c
+    tests/mem_test.h
     )
 target_link_libraries(mem_test
     cii_static
     )
 
 add_executable(list_test
-    src/list_test.c
+    tests/list_test.c
     )
 target_link_libraries(list_test
     cii_static
diff --git a/cii/tests/get_word.h b/cii/tests/get_word.h
new file mode 100644
index 00000000..64a5d3d1
--- /dev/null
+++ b/cii/tests/get_word.h
@@ -0,0 +1,8 @@
+// Copyright (c) 2023 Xu Shaohua <shaohua@biofan.org>. All rights reserved.
+// Use of this source is governed by GNU General Public License
+// that can be found in the LICENSE file.
+
+#ifndef CII_TESTS_GET_WORD_H_
+#define CII_TESTS_GET_WORD_H_
+
+#endif //CII_TESTS_GET_WORD_H_
diff --git a/cii/src/list_test.c b/cii/tests/list_test.c
similarity index 100%
rename from cii/src/list_test.c
rename to cii/tests/list_test.c
diff --git a/cii/src/mem_test.c b/cii/tests/mem_test.c
similarity index 100%
rename from cii/src/mem_test.c
rename to cii/tests/mem_test.c
diff --git a/cii/src/mem_test.h b/cii/tests/mem_test.h
similarity index 90%
rename from cii/src/mem_test.h
rename to cii/tests/mem_test.h
index b576f600..b28cd7c8 100644
--- a/cii/src/mem_test.h
+++ b/cii/tests/mem_test.h
@@ -2,8 +2,8 @@
 // Use of this source is governed by GNU General Public License
 // that can be found in the LICENSE file.
 
-#ifndef CII_SRC_MEM_TEST_H_
-#define CII_SRC_MEM_TEST_H_
+#ifndef CII_TESTS_MEM_TEST_H_
+#define CII_TESTS_MEM_TEST_H_
 
 #include <stdlib.h>
 
@@ -33,4 +33,4 @@ typedef struct descriptor_s descriptor_t;
  */
 descriptor_t* find_node(const void* ptr);
 
-#endif //CII_SRC_MEM_TEST_H_
+#endif //CII_TESTS_MEM_TEST_H_