add test lib source and header

include/commons.cpp

@@ -0,0 +1,7 @@
+#include "commons.hpp"
+#include <boost/asio.hpp>
+
+void Test::Hello() const
+{
+    std::cout << "Hello World\n";
+}

include/commons.hpp

@@ -0,0 +1,8 @@
+#pragma once
+
+#include <iostream>
+
+class Test
+{
+    void Hello() const;
+};