diff --git a/test/global/common_code.cc b/test/global/common_code.cc
index e9cfbf1..b74e828 100644
--- a/test/global/common_code.cc
+++ b/test/global/common_code.cc
@@ -1,7 +1,9 @@
+#include "all_cases.h"
 #include "gtest/gtest.h"
 #include "common_code.h"
 #include "global_utils.h"
 
+using klotski::AllCases;
 using klotski::CommonCode;
 
 std::vector<uint64_t> common_code_search(uint64_t start, uint64_t end) {
@@ -14,16 +16,31 @@ std::vector<uint64_t> common_code_search(uint64_t start, uint64_t end) {
     return ret;
 }
 
-
 TEST(GLOBAL, common_code) {
+    /// create common code check tasks
+    auto pool = TinyPool(thread_num());
+    std::vector<std::future<std::vector<uint64_t>>> futures;
+    for (const auto &range : range_split(0, 0x10'0000'0000, 0x10'0000)) {
+        futures.emplace_back(
+            pool.submit(common_code_search, range.first, range.second)
+        );
+    }
 
-//    auto ranges = range_split(0, 100, 30);
-//    auto ranges = range_split(0, 91, 30);
-//    auto ranges = range_split(0, 89, 30);
-    auto ranges = range_split(0, 90, 30);
-
-    for (const auto &r : ranges) {
-        printf("[%lu, %lu)\n", r.first, r.second);
+    /// run common code search
+    pool.boot();
+    std::vector<uint64_t> result;
+    for (auto &f : futures) {
+        auto ret = f.get();
+        result.insert(result.end(), ret.begin(), ret.end());
     }
+    pool.join();
 
+    /// verify check result
+    std::vector<uint64_t> all_cases;
+    for (uint64_t head = 0; head < 16; ++head) {
+        for (const auto &range : AllCases::fetch()[head]) {
+            all_cases.emplace_back(head << 32 | range);
+        }
+    }
+    EXPECT_EQ(result, all_cases);
 }
diff --git a/test/global/global_utils.cc b/test/global/global_utils.cc
index 7f01cad..786ffb2 100644
--- a/test/global/global_utils.cc
+++ b/test/global/global_utils.cc
@@ -1,21 +1,5 @@
 #include "global_utils.h"
 
-template <typename Func, typename ...Args>
-auto TinyPool::submit(Func &&func, Args &&...args) -> std::future<decltype(func(args...))> {
-    std::function<decltype(func(args...))()> wrap_func = std::bind(
-        std::forward<Func>(func), std::forward<Args>(args)...
-    );
-    auto func_ptr = std::make_shared<
-        std::packaged_task<decltype(func(args...))()>
-    >(wrap_func);
-    tiny_pool_submit(pool, TinyPool::wrap_c_func, (void*)(
-        new std::function<void()> (
-            [func_ptr]() { (*func_ptr)(); }
-        )
-    ));
-    return func_ptr->get_future();
-}
-
 range_split_t range_split(uint64_t start, uint64_t end, uint64_t size) {
     uint64_t rear = end - (end - start) % size; // (rear - start) % size == 0
     range_split_t ranges;
@@ -27,3 +11,10 @@ range_split_t range_split(uint64_t start, uint64_t end, uint64_t size) {
     }
     return ranges;
 }
+
+uint32_t thread_num() {
+
+    // TODO: use CPU core number
+
+    return 16;
+}
diff --git a/test/global/global_utils.h b/test/global/global_utils.h
index 2ac533c..beb00fd 100644
--- a/test/global/global_utils.h
+++ b/test/global/global_utils.h
@@ -1,8 +1,15 @@
+#pragma once
+
 #include <future>
 #include <vector>
 #include <functional>
 #include "tiny_pool.h"
 
+uint32_t thread_num();
+
+typedef std::vector<std::pair<uint64_t, uint64_t>> range_split_t;
+range_split_t range_split(uint64_t start, uint64_t end, uint64_t size);
+
 class TinyPool { // OOP for tiny_thread_pool
     pool_t *pool;
     static void wrap_c_func(void *func) { // wrap std::function as c-style function ptr
@@ -19,9 +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...))> {
+        std::function<decltype(func(args...))()> wrap_func = std::bind(
+            std::forward<Func>(func), std::forward<Args>(args)...
+        );
+        auto func_ptr = std::make_shared<
+            std::packaged_task<decltype(func(args...))()>
+        >(wrap_func);
+        tiny_pool_submit(pool, TinyPool::wrap_c_func, (void*)(
+            new std::function<void()> (
+                [func_ptr]() { (*func_ptr)(); }
+            )
+        ));
+        return func_ptr->get_future();
+    }
 };
-
-typedef std::vector<std::pair<uint64_t, uint64_t>> range_split_t;
-
-range_split_t range_split(uint64_t start, uint64_t end, uint64_t size);