diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index df91664..5f94a1e 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -59,9 +59,13 @@ add_library(test_global_utils STATIC global/global_utils.cc)
 set(TEST_GLOBAL_DEPS ${TEST_DEPS} test_global_utils tiny_pool)
 
 include_directories(../src/klotski_core/common_code)
-
 add_executable(test_global_common_code global/common_code.cc)
 target_link_libraries(test_global_common_code ${TEST_GLOBAL_DEPS})
 add_test(NAME global_common_code COMMAND test_global_common_code)
 
+include_directories(../src/klotski_core/short_code)
+add_executable(test_global_short_code global/short_code.cc)
+target_link_libraries(test_global_short_code ${TEST_GLOBAL_DEPS})
+add_test(NAME global_short_code COMMAND test_global_short_code)
+
 ################################################################################
diff --git a/test/global/global_utils.h b/test/global/global_utils.h
index beb00fd..05aee9f 100644
--- a/test/global/global_utils.h
+++ b/test/global/global_utils.h
@@ -15,7 +15,7 @@ class TinyPool { // OOP for tiny_thread_pool
     static void wrap_c_func(void *func) { // wrap std::function as c-style function ptr
         auto func_ptr = static_cast<std::function<void()>*>(func);
         (*func_ptr)();
-        delete func_ptr;
+        delete func_ptr; // free lambda function
     }
 
 public:
@@ -26,18 +26,18 @@ public:
     explicit TinyPool(uint32_t size) { pool = tiny_pool_create(size); }
 
     template <typename Func, typename ...Args>
-    auto submit(Func &&func, Args &&...args) -> std::future<decltype(func(args...))> {
+    auto submit(Func &&func, Args &&...args) -> std::future<decltype(func(args...))> { // submit new task
         std::function<decltype(func(args...))()> wrap_func = std::bind(
-            std::forward<Func>(func), std::forward<Args>(args)...
+            std::forward<Func>(func), std::forward<Args>(args)... // wrap as a function without params
         );
         auto func_ptr = std::make_shared<
-            std::packaged_task<decltype(func(args...))()>
+            std::packaged_task<decltype(func(args...))()> // function task as shared ptr
         >(wrap_func);
-        tiny_pool_submit(pool, TinyPool::wrap_c_func, (void*)(
+        tiny_pool_submit(pool, TinyPool::wrap_c_func, (void*)( // submit with thread pool interface
             new std::function<void()> (
-                [func_ptr]() { (*func_ptr)(); }
+                [func_ptr]() { (*func_ptr)(); } // create lambda for running task
             )
         ));
-        return func_ptr->get_future();
+        return func_ptr->get_future(); // return future object
     }
 };
diff --git a/test/global/short_code.cc b/test/global/short_code.cc
new file mode 100644
index 0000000..d55ad39
--- /dev/null
+++ b/test/global/short_code.cc
@@ -0,0 +1,37 @@
+#include "gtest/gtest.h"
+#include "short_code.h"
+
+using klotski::ShortCode;
+using klotski::CommonCode;
+
+std::vector<uint64_t> short_code_check(uint32_t start, uint32_t end) {
+
+    // TODO: give me short_code range -> convert to common_code and archive it
+    //       common_code convert to short_code -> verify normal mode
+
+    std::vector<uint64_t> archive;
+
+    for (uint32_t short_code = start; short_code < end; ++short_code) {
+
+        auto common_code = ShortCode::unsafe_create(short_code).to_common_code();
+
+        archive.emplace_back(common_code.unwrap());
+
+        EXPECT_EQ(common_code.to_short_code().unwrap(), short_code);
+
+    }
+
+    return archive;
+
+}
+
+TEST(GLOBAL, short_code) {
+
+    ShortCode::speed_up(ShortCode::NORMAL);
+
+    auto r = short_code_check(0, 100);
+
+    std::cout << r.size() << std::endl;
+
+
+}