add new test file

Signed-off-by: Ujjwal Shekhar <ujjwal.shekhar@research.iiit.ac.in>

Author: ujjwal-shekhar

libs/core/serialization/tests/unit/refl/reflection_qualified_name_of.cpp

@@ -0,0 +1,74 @@
+//  Copyright (c) 2026 Ujjwal Shekhar
+//  SPDX-License-Identifier: BSL-1.0
+//  Distributed under the Boost Software License, Version 1.0. (See accompanying
+//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include <hpx/config.hpp>
+#include <hpx/modules/serialization.hpp>
+#include <hpx/modules/testing.hpp>
+
+#include <string>
+#include <vector>
+
+namespace empty_space {
+    template <typename... Args>
+    struct void_void {};
+}
+
+namespace a::b::c::d {
+    template <typename T1, typename T2, typename T3, typename T4, typename T5>
+    struct pentagon {};
+}
+
+namespace world {
+    namespace continent {
+        namespace country {
+            template <typename T>
+            struct city {};
+        }
+    }
+}
+
+namespace local {
+    struct person {};
+}
+
+int main()
+{
+    using hpx::serialization::detail::qualified_name_of;
+
+    // Empty/Variadic Template Test
+    {
+        using type = empty_space::void_void<>;
+        char const* name = qualified_name_of<type>::get();
+        HPX_TEST(name != nullptr);
+        HPX_TEST_EQ(std::string(name), std::string("empty_space::void_void<>"));
+    }
+
+    // Deep Namespace + High Arity
+    {
+        using type = a::b::c::d::pentagon<int, char, double, float, long>;
+        char const* name = qualified_name_of<type>::get();
+        HPX_TEST_EQ(std::string(name), 
+            std::string("a::b::c::d::pentagon<int,char,double,float,long>"));
+    }
+
+    // Deeply Nested Custom Types as Template Args
+    {
+        // City containing a Person from a different namespace
+        using nested_type = world::continent::country::city<local::person>;
+        
+        // Wrap that in ANOTHER layer
+        using deeper_nested_type = world::continent::country::city<nested_type>;
+        
+        char const* name = qualified_name_of<deeper_nested_type>::get();
+        
+        // Expected: world::continent::country::city<world::continent::country::city<local::person>>
+        std::string expected = "world::continent::country::city<"
+                               "world::continent::country::city<local::person>>";
+        
+        HPX_TEST_EQ(std::string(name), expected);
+    }
+
+    return hpx::util::report_errors();
+}