diff --git a/CMakePresets.json b/CMakePresets.json
index 8f412dd..b84fafb 100644
--- a/CMakePresets.json
+++ b/CMakePresets.json
@@ -17,7 +17,8 @@
             "inherits": "default",
             "cacheVariables": {
                 "FISHBONE_BUILD_TESTS": "ON",
-                "CMAKE_EXPORT_COMPILE_COMMANDS": "ON"
+                "CMAKE_EXPORT_COMPILE_COMMANDS": "ON",
+                "CMAKE_BUILD_TYPE": "Debug"
             }
         }
     ],
diff --git a/engine/include/fishbone/machdep.h b/engine/include/fishbone/machdep.h
index 8e7b4ac..e6588ef 100644
--- a/engine/include/fishbone/machdep.h
+++ b/engine/include/fishbone/machdep.h
@@ -4,6 +4,7 @@
 #include <vector>
 #include <string>
 #include <fstream>
+#include <functional>
 
 #include <cstdio>
 #include <cstring>
diff --git a/engine/include/fishbone/thread.h b/engine/include/fishbone/thread.h
index 014bd9b..1833780 100644
--- a/engine/include/fishbone/thread.h
+++ b/engine/include/fishbone/thread.h
@@ -14,7 +14,11 @@ namespace fishbone {
 		Impl* impl;
 
 	    public:
-		Thread(void (*call)(fishbone::Thread* thread, void* arg), void* arg);
+		using Callable = void(*)(fishbone::Thread* thread, void* arg);
+		using CallableFunc = std::function<void(fishbone::Thread* thread)>;
+
+		Thread(Callable call, void* arg);
+		Thread(CallableFunc call);
 		~Thread();
 
 		void join();
diff --git a/engine/src/thread/sdl2.cc b/engine/src/thread/sdl2.cc
index 7f99e6f..7b0ffa4 100644
--- a/engine/src/thread/sdl2.cc
+++ b/engine/src/thread/sdl2.cc
@@ -3,9 +3,14 @@
 #include <fishbone/foundation.h>
 
 struct call_arg {
-	void (*call)(fishbone::Thread* thread, void* arg);
-	fishbone::Thread* thread;
-	void*		  arg;
+	fishbone::Thread::Callable	call;
+	fishbone::Thread* 		thread;
+	void*		  		arg;
+};
+
+struct call_arg2 {
+	fishbone::Thread::CallableFunc	call;
+	fishbone::Thread* 		thread;
 };
 
 static int SDLCALL thread_call(void* data) {
@@ -18,11 +23,21 @@ static int SDLCALL thread_call(void* data) {
 	return 0;
 }
 
+static int SDLCALL thread_call2(void* data) {
+	struct call_arg2* arg = (struct call_arg2*)data;
+
+	arg->call(arg->thread);
+
+	delete arg;
+
+	return 0;
+}
+
 struct fishbone::Thread::Impl {
 	SDL_Thread* thread;
 };
 
-fishbone::Thread::Thread(void (*call)(fishbone::Thread* thread, void* arg), void* arg) {
+fishbone::Thread::Thread(Callable call, void* arg) {
 	struct call_arg* data = new struct call_arg();
 
 	data->call   = call;
@@ -33,6 +48,16 @@ fishbone::Thread::Thread(void (*call)(fishbone::Thread* thread, void* arg), void
 	this->impl->thread = SDL_CreateThread(thread_call, "FBThread", data);
 }
 
+fishbone::Thread::Thread(CallableFunc call) {
+	struct call_arg2* data = new struct call_arg2();
+
+	data->call   = call;
+	data->thread = this;
+
+	this->impl	   = new fishbone::Thread::Impl();
+	this->impl->thread = SDL_CreateThread(thread_call2, "FBThread", data);
+}
+
 fishbone::Thread::~Thread() {
 	this->join();
 }
diff --git a/engine/tests/src/placeholder.cc b/engine/tests/src/placeholder.cc
deleted file mode 100644
index 96821ce..0000000
--- a/engine/tests/src/placeholder.cc
+++ /dev/null
@@ -1 +0,0 @@
-#include <catch2/catch_test_macros.hpp>
diff --git a/engine/tests/src/thread.cc b/engine/tests/src/thread.cc
new file mode 100644
index 0000000..f2f8811
--- /dev/null
+++ b/engine/tests/src/thread.cc
@@ -0,0 +1,59 @@
+#include "fishbone/thread.h"
+#include <catch2/catch_test_macros.hpp>
+#include <cstdio>
+#include <cstdlib>
+#include <unistd.h>
+
+struct thread_arg {
+    int& a;
+};
+
+TEST_CASE("Thread") {
+    int a = 0;
+
+    fishbone::Thread th([&a](auto) {
+        for (int i = 0; i < 100; i++) {
+            a++;
+        }
+    });
+
+    th.join();
+    REQUIRE(a == 100);
+    
+    a = 0;
+
+    thread_arg arg { a };
+    fishbone::Thread th2([](auto, void* data) {
+        thread_arg& arg = *static_cast<thread_arg*>(data);
+
+        for (int i = 0; i < 100; i++) {
+            arg.a++;
+        }
+    }, &arg);
+
+    th.join();
+    REQUIRE(a == 100);
+}
+
+TEST_CASE("Mutex") {
+    for (int i = 0; i < 100; i++) {
+        int a = 0;
+        fishbone::Mutex m;
+
+        fishbone::Thread::CallableFunc func = [&a, &m](auto) {
+            m.lock();
+            for (int j = 0; j < 2; j++) {
+                int b = a;
+                usleep((60 * rand()) / RAND_MAX);
+                a = ++b;
+            }
+            m.unlock();
+        };
+
+        fishbone::Thread th1(func), th2(func);
+
+        th1.join();
+        th2.join();
+        REQUIRE(a == 4);
+    }
+}
\ No newline at end of file