diff --git a/.zed/debug.json b/.zed/debug.json
new file mode 100644
index 0000000..72e67ce
--- /dev/null
+++ b/.zed/debug.json
@@ -0,0 +1,17 @@
+// Project-local debug tasks
+//
+// For more documentation on how to configure debug tasks,
+// see: https://zed.dev/docs/debugger
+[
+  {
+    "label": "Debug Test",
+    "build": {
+      "command": "make",
+      "args": ["-j8"],
+      "cwd": "$ZED_WORKTREE_ROOT/build",
+    },
+    "program": "$ZED_WORKTREE_ROOT/build/camellya_tests",
+    "request": "launch",
+    "adapter": "GDB",
+  },
+]
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1c7176f..2ce498c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -69,6 +69,9 @@ if(CAMELLYA_BUILD_TESTS)
         tests/test_basic.cpp
         tests/test_utf8.cpp
         tests/test_vm.cpp
+        tests/test_list.cpp
+        tests/test_map_builtin.cpp
+        tests/test_generic_builtin.cpp
     )
 
     target_include_directories(camellya_tests
diff --git a/src/camellya.cpp b/src/camellya.cpp
index 2c1ae8e..9b9521a 100644
--- a/src/camellya.cpp
+++ b/src/camellya.cpp
@@ -71,10 +71,13 @@ bool Camellya::do_file(const std::string &filename) {
 }
 
 void Camellya::register_function(const std::string &name, NativeFunction func) {
-  auto func_value = std::make_shared<FunctionValue>(name, func);
   d->vm->register_native_function(name, func);
 }
 
+void Camellya::register_builtin_class(const std::string &type_name, std::shared_ptr<ClassValue> klass) {
+  d->vm->register_builtin_class(type_name, klass);
+}
+
 int Camellya::get_top() const { return static_cast<int>(d->stack.size()); }
 ValuePtr Camellya::get_global(const std::string &name) {
   return d->vm->get_global(name);
diff --git a/src/camellya.h b/src/camellya.h
index 000e52e..43ec679 100644
--- a/src/camellya.h
+++ b/src/camellya.h
@@ -23,6 +23,9 @@ public:
   // Register native function
   void register_function(const std::string &name, NativeFunction func);
 
+  // Register built-in class for any type (including user native types)
+  void register_builtin_class(const std::string &type_name, std::shared_ptr<ClassValue> klass);
+
   // Get global variable
   ValuePtr get_global(const std::string &name);
 
diff --git a/src/value.cpp b/src/value.cpp
index 42e29e4..f69027d 100644
--- a/src/value.cpp
+++ b/src/value.cpp
@@ -1,124 +1,125 @@
 #include "value.h"
-#include <sstream>
-#include <iomanip>
 #include <cmath>
+#include <iomanip>
+#include <sstream>
 
 namespace camellya {
 
 std::string NumberValue::to_string() const {
-    if (std::floor(value) == value) {
-        return std::to_string(static_cast<int64_t>(value));
-    }
-    std::ostringstream oss;
-    oss << std::fixed << std::setprecision(6) << value;
-    std::string str = oss.str();
-    str.erase(str.find_last_not_of('0') + 1, std::string::npos);
-    if (str.back() == '.') str.pop_back();
-    return str;
+  if (std::floor(value) == value) {
+    return std::to_string(static_cast<int64_t>(value));
+  }
+  std::ostringstream oss;
+  oss << std::fixed << std::setprecision(6) << value;
+  std::string str = oss.str();
+  str.erase(str.find_last_not_of('0') + 1, std::string::npos);
+  if (str.back() == '.')
+    str.pop_back();
+  return str;
 }
 
 std::string ListValue::to_string() const {
-    std::ostringstream oss;
-    oss << "[";
-    for (size_t i = 0; i < elements.size(); ++i) {
-        if (i > 0) oss << ", ";
-        oss << elements[i]->to_string();
-    }
-    oss << "]";
-    return oss.str();
+  std::ostringstream oss;
+  oss << "[";
+  for (size_t i = 0; i < elements.size(); ++i) {
+    if (i > 0)
+      oss << ", ";
+    oss << elements[i]->to_string();
+  }
+  oss << "]";
+  return oss.str();
 }
 
 ValuePtr ListValue::clone() const {
-    std::vector<ValuePtr> cloned_elements;
-    cloned_elements.reserve(elements.size());
-    for (const auto& elem : elements) {
-        cloned_elements.push_back(elem->clone());
-    }
-    return std::make_shared<ListValue>(std::move(cloned_elements));
+  std::vector<ValuePtr> cloned_elements;
+  cloned_elements.reserve(elements.size());
+  for (const auto &elem : elements) {
+    cloned_elements.push_back(elem->clone());
+  }
+  return std::make_shared<ListValue>(std::move(cloned_elements));
 }
 
 ValuePtr ListValue::get(size_t index) const {
-    if (index >= elements.size()) {
-        return std::make_shared<NilValue>();
-    }
-    return elements[index];
+  if (index >= elements.size()) {
+    return std::make_shared<NilValue>();
+  }
+  return elements[index];
 }
 
 void ListValue::set(size_t index, ValuePtr value) {
-    if (index >= elements.size()) {
-        elements.resize(index + 1, std::make_shared<NilValue>());
-    }
-    elements[index] = std::move(value);
+  if (index >= elements.size()) {
+    elements.resize(index + 1, std::make_shared<NilValue>());
+  }
+  elements[index] = std::move(value);
 }
 
 std::string MapValue::to_string() const {
-    std::ostringstream oss;
-    oss << "{";
-    bool first = true;
-    for (const auto& [key, value] : pairs) {
-        if (!first) oss << ", ";
-        first = false;
-        oss << key << ": " << value->to_string();
-    }
-    oss << "}";
-    return oss.str();
+  std::ostringstream oss;
+  oss << "{";
+  bool first = true;
+  for (const auto &[key, value] : pairs) {
+    if (!first)
+      oss << ", ";
+    first = false;
+    oss << key << ": " << value->to_string();
+  }
+  oss << "}";
+  return oss.str();
 }
 
 ValuePtr MapValue::clone() const {
-    std::map<std::string, ValuePtr> cloned_pairs;
-    for (const auto& [key, value] : pairs) {
-        cloned_pairs[key] = value->clone();
-    }
-    return std::make_shared<MapValue>(std::move(cloned_pairs));
+  std::map<std::string, ValuePtr> cloned_pairs;
+  for (const auto &[key, value] : pairs) {
+    cloned_pairs[key] = value->clone();
+  }
+  return std::make_shared<MapValue>(std::move(cloned_pairs));
 }
 
-ValuePtr MapValue::get(const std::string& key) const {
-    auto it = pairs.find(key);
-    if (it == pairs.end()) {
-        return std::make_shared<NilValue>();
-    }
-    return it->second;
+ValuePtr MapValue::get(const std::string &key) const {
+  auto it = pairs.find(key);
+  if (it == pairs.end()) {
+    return std::make_shared<NilValue>();
+  }
+  return it->second;
 }
 
 ValuePtr ClassValue::clone() const {
-    auto cloned = std::make_shared<ClassValue>(name);
-    cloned->fields = fields;
-    cloned->methods = methods;
-    return cloned;
+  auto cloned = std::make_shared<ClassValue>(name);
+  cloned->fields = fields;
+  cloned->methods = methods;
+  return cloned;
 }
 
 ValuePtr InstanceValue::clone() const {
-    auto cloned = std::make_shared<InstanceValue>(klass);
-    for (const auto& [key, value] : fields) {
-        cloned->fields[key] = value->clone();
-    }
-    return cloned;
+  auto cloned = std::make_shared<InstanceValue>(klass);
+  for (const auto &[key, value] : fields) {
+    cloned->fields[key] = value->clone();
+  }
+  return cloned;
 }
 
-ValuePtr InstanceValue::get(const std::string& name) const {
-    // First check fields
-    auto field_it = fields.find(name);
-    if (field_it != fields.end()) {
-        return field_it->second;
-    }
-    
-    // Then check methods and bind 'this'
-    auto method_it = klass->methods.find(name);
-    if (method_it != klass->methods.end()) {
-        auto bound = std::make_shared<FunctionValue>(*method_it->second);
-        auto self = std::static_pointer_cast<InstanceValue>(
-            const_cast<InstanceValue*>(this)->shared_from_this());
-        bound->bound_instance = self;
-        return bound;
-    }
-    
-    return std::make_shared<NilValue>();
+ValuePtr InstanceValue::get(const std::string &name) const {
+  // First check fields
+  auto field_it = fields.find(name);
+  if (field_it != fields.end()) {
+    return field_it->second;
+  }
+
+  // Then check methods and bind 'this'
+  auto method_it = klass->methods.find(name);
+  if (method_it != klass->methods.end()) {
+    auto bound = std::make_shared<FunctionValue>(*method_it->second);
+    bound->bound_instance = const_cast<InstanceValue *>(this)->shared_from_this();
+    return bound;
+  }
+
+  return std::make_shared<NilValue>();
 }
 
-void InstanceValue::set(const std::string& name, ValuePtr value) {
-    if (fields.find(name) != fields.end()) {
-        fields[name] = std::move(value);
-    }
+void InstanceValue::set(const std::string &name, ValuePtr value) {
+  if (fields.find(name) != fields.end()) {
+    fields[name] = std::move(value);
+  }
 }
 
 } // namespace camellya
diff --git a/src/value.h b/src/value.h
index 55ea2f6..48d22b6 100644
--- a/src/value.h
+++ b/src/value.h
@@ -24,13 +24,15 @@ enum class Type {
     MAP,
     FUNCTION,
     CLASS,
-    INSTANCE
+    INSTANCE,
+    NATIVE
 };
 
-class Value {
+class Value : public std::enable_shared_from_this<Value> {
 public:
     virtual ~Value() = default;
     virtual Type type() const = 0;
+    virtual std::string type_name() const = 0;
     virtual std::string to_string() const = 0;
     virtual ValuePtr clone() const = 0;
 };
@@ -38,6 +40,7 @@ public:
 class NilValue : public Value {
 public:
     Type type() const override { return Type::NIL; }
+    std::string type_name() const override { return "nil"; }
     std::string to_string() const override { return "nil"; }
     ValuePtr clone() const override { return std::make_shared<NilValue>(); }
 };
@@ -48,6 +51,7 @@ public:
     
     explicit NumberValue(double value) : value(value) {}
     Type type() const override { return Type::NUMBER; }
+    std::string type_name() const override { return "number"; }
     std::string to_string() const override;
     ValuePtr clone() const override { return std::make_shared<NumberValue>(value); }
 };
@@ -58,6 +62,7 @@ public:
     
     explicit StringValue(std::string value) : value(std::move(value)) {}
     Type type() const override { return Type::STRING; }
+    std::string type_name() const override { return "string"; }
     std::string to_string() const override { return value; }
     ValuePtr clone() const override { return std::make_shared<StringValue>(value); }
 };
@@ -68,6 +73,7 @@ public:
     
     explicit BoolValue(bool value) : value(value) {}
     Type type() const override { return Type::BOOL; }
+    std::string type_name() const override { return "bool"; }
     std::string to_string() const override { return value ? "true" : "false"; }
     ValuePtr clone() const override { return std::make_shared<BoolValue>(value); }
 };
@@ -80,6 +86,7 @@ public:
     explicit ListValue(std::vector<ValuePtr> elements) : elements(std::move(elements)) {}
     
     Type type() const override { return Type::LIST; }
+    std::string type_name() const override { return "list"; }
     std::string to_string() const override;
     ValuePtr clone() const override;
     
@@ -97,6 +104,7 @@ public:
     explicit MapValue(std::map<std::string, ValuePtr> pairs) : pairs(std::move(pairs)) {}
     
     Type type() const override { return Type::MAP; }
+    std::string type_name() const override { return "map"; }
     std::string to_string() const override;
     ValuePtr clone() const override;
     
@@ -120,12 +128,12 @@ public:
     std::shared_ptr<Chunk> chunk;
     NativeFunction native_func;
     bool is_native;
-    std::shared_ptr<InstanceValue> bound_instance;
+    ValuePtr bound_instance;
     
     // Script function
     FunctionValue(std::string name, std::shared_ptr<FunctionDecl> declaration,
                   std::shared_ptr<Chunk> chunk = nullptr,
-                  std::shared_ptr<InstanceValue> bound_instance = nullptr)
+                  ValuePtr bound_instance = nullptr)
         : name(std::move(name)), declaration(std::move(declaration)),
           chunk(std::move(chunk)), is_native(false), 
           bound_instance(std::move(bound_instance)) {}
@@ -135,6 +143,7 @@ public:
         : name(std::move(name)), native_func(std::move(func)), is_native(true) {}
     
     Type type() const override { return Type::FUNCTION; }
+    std::string type_name() const override { return "function"; }
     std::string to_string() const override { return "<function " + name + ">"; }
     ValuePtr clone() const override { return std::make_shared<FunctionValue>(*this); }
 };
@@ -148,6 +157,7 @@ public:
     explicit ClassValue(std::string name) : name(std::move(name)) {}
     
     Type type() const override { return Type::CLASS; }
+    std::string type_name() const override { return "class"; }
     std::string to_string() const override { return "<class " + name + ">"; }
     ValuePtr clone() const override;
     
@@ -160,7 +170,7 @@ public:
     }
 };
 
-class InstanceValue : public Value, public std::enable_shared_from_this<InstanceValue> {
+class InstanceValue : public Value {
 public:
     std::shared_ptr<ClassValue> klass;
     std::map<std::string, ValuePtr> fields;
@@ -173,6 +183,7 @@ public:
     }
     
     Type type() const override { return Type::INSTANCE; }
+    std::string type_name() const override { return klass->name; }
     std::string to_string() const override { return "<instance of " + klass->name + ">"; }
     ValuePtr clone() const override;
     
@@ -180,6 +191,18 @@ public:
     void set(const std::string& name, ValuePtr value);
 };
 
+class NativeValue : public Value {
+public:
+    std::string _type_name;
+    
+    explicit NativeValue(std::string type_name) : _type_name(std::move(type_name)) {}
+    
+    Type type() const override { return Type::NATIVE; }
+    std::string type_name() const override { return _type_name; }
+    std::string to_string() const override { return "<native " + _type_name + ">"; }
+    ValuePtr clone() const override { return std::make_shared<NativeValue>(_type_name); }
+};
+
 // Helper functions
 inline bool is_truthy(const ValuePtr& value) {
     if (!value || value->type() == Type::NIL) return false;
diff --git a/src/vm.cpp b/src/vm.cpp
index a9f1908..45b61b4 100644
--- a/src/vm.cpp
+++ b/src/vm.cpp
@@ -1,5 +1,4 @@
 #include "vm.h"
-#include "interpreter.h"
 #include <iostream>
 #include <format>
 #include <cmath>
@@ -212,6 +211,9 @@ bool VM::run() {
                     if (func->is_native) {
                         // Native function call
                         std::vector<ValuePtr> args;
+                        if (func->bound_instance) {
+                            args.push_back(func->bound_instance);
+                        }
                         for (int i = arg_count - 1; i >= 0; i--) {
                             args.push_back(peek(i));
                         }
@@ -424,7 +426,18 @@ bool VM::run() {
                     auto instance = std::dynamic_pointer_cast<InstanceValue>(object);
                     push(instance->get(name));
                 } else {
-                    runtime_error("Only instances have properties.");
+                    auto it = builtin_classes.find(object->type_name());
+                    if (it != builtin_classes.end()) {
+                        auto klass = it->second;
+                        auto method_it = klass->methods.find(name);
+                        if (method_it != klass->methods.end()) {
+                            auto bound = std::make_shared<FunctionValue>(*method_it->second);
+                            bound->bound_instance = object;
+                            push(bound);
+                            break;
+                        }
+                    }
+                    runtime_error("Only instances and types with registered built-in classes have properties/methods.");
                     return false;
                 }
                 break;
@@ -613,6 +626,67 @@ void VM::register_builtin_functions() {
             throw RuntimeError("len() expects list, string, or map.");
         });
     globals["len"] = len_func;
+
+    // Define list class
+    auto list_klass = std::make_shared<ClassValue>("list");
+    list_klass->add_method("push", std::make_shared<FunctionValue>("push",
+        [](const std::vector<ValuePtr>& args) -> ValuePtr {
+            if (args.size() != 2) throw RuntimeError("list.push() expects 1 argument.");
+            auto list = std::dynamic_pointer_cast<ListValue>(args[0]);
+            list->push(args[1]);
+            return args[1];
+        }));
+    list_klass->add_method("pop", std::make_shared<FunctionValue>("pop",
+        [](const std::vector<ValuePtr>& args) -> ValuePtr {
+            if (args.size() != 1) throw RuntimeError("list.pop() expects 0 arguments.");
+            auto list = std::dynamic_pointer_cast<ListValue>(args[0]);
+            if (list->elements.empty()) return std::make_shared<NilValue>();
+            ValuePtr val = list->elements.back();
+            list->elements.pop_back();
+            return val;
+        }));
+    list_klass->add_method("len", std::make_shared<FunctionValue>("len",
+        [](const std::vector<ValuePtr>& args) -> ValuePtr {
+            if (args.size() != 1) throw RuntimeError("list.len() expects 0 arguments.");
+            auto list = std::dynamic_pointer_cast<ListValue>(args[0]);
+            return std::make_shared<NumberValue>(static_cast<double>(list->size()));
+        }));
+    register_builtin_class("list", list_klass);
+
+    // Define map class
+    auto map_klass = std::make_shared<ClassValue>("map");
+    map_klass->add_method("set", std::make_shared<FunctionValue>("set",
+        [](const std::vector<ValuePtr>& args) -> ValuePtr {
+            if (args.size() != 3) throw RuntimeError("map.set() expects 2 arguments.");
+            auto map = std::dynamic_pointer_cast<MapValue>(args[0]);
+            if (args[1]->type() != Type::STRING) throw RuntimeError("Map key must be a string.");
+            std::string key = std::dynamic_pointer_cast<StringValue>(args[1])->value;
+            map->set(key, args[2]);
+            return args[2];
+        }));
+    map_klass->add_method("get", std::make_shared<FunctionValue>("get",
+        [](const std::vector<ValuePtr>& args) -> ValuePtr {
+            if (args.size() != 2) throw RuntimeError("map.get() expects 1 argument.");
+            auto map = std::dynamic_pointer_cast<MapValue>(args[0]);
+            if (args[1]->type() != Type::STRING) throw RuntimeError("Map key must be a string.");
+            std::string key = std::dynamic_pointer_cast<StringValue>(args[1])->value;
+            return map->get(key);
+        }));
+    map_klass->add_method("has", std::make_shared<FunctionValue>("has",
+        [](const std::vector<ValuePtr>& args) -> ValuePtr {
+            if (args.size() != 2) throw RuntimeError("map.has() expects 1 argument.");
+            auto map = std::dynamic_pointer_cast<MapValue>(args[0]);
+            if (args[1]->type() != Type::STRING) throw RuntimeError("Map key must be a string.");
+            std::string key = std::dynamic_pointer_cast<StringValue>(args[1])->value;
+            return std::make_shared<BoolValue>(map->has(key));
+        }));
+    map_klass->add_method("len", std::make_shared<FunctionValue>("len",
+        [](const std::vector<ValuePtr>& args) -> ValuePtr {
+            if (args.size() != 1) throw RuntimeError("map.len() expects 0 arguments.");
+            auto map = std::dynamic_pointer_cast<MapValue>(args[0]);
+            return std::make_shared<NumberValue>(static_cast<double>(map->pairs.size()));
+        }));
+    register_builtin_class("map", map_klass);
 }
 
 void VM::register_native_function(const std::string& name, NativeFunction func) {
@@ -620,6 +694,11 @@ void VM::register_native_function(const std::string& name, NativeFunction func)
     globals[name] = func_value;
 }
 
+void VM::register_builtin_class(const std::string& type_name, std::shared_ptr<ClassValue> klass) {
+    builtin_classes[type_name] = klass;
+    globals[klass->name] = klass;
+}
+
 void VM::set_global(const std::string& name, ValuePtr value) {
     globals[name] = value;
 }
diff --git a/src/vm.h b/src/vm.h
index 891f04f..23a1793 100644
--- a/src/vm.h
+++ b/src/vm.h
@@ -34,6 +34,9 @@ public:
     // Register native functions
     void register_native_function(const std::string& name, NativeFunction func);
     
+    // Register built-in classes for types (like list, map)
+    void register_builtin_class(const std::string& type_name, std::shared_ptr<ClassValue> klass);
+    
     // Global variable access
     void set_global(const std::string& name, ValuePtr value);
     ValuePtr get_global(const std::string& name);
@@ -48,6 +51,7 @@ private:
     std::vector<CallFrame> frames;
     CallFrame* current_frame;
     std::map<std::string, ValuePtr> globals;
+    std::map<std::string, std::shared_ptr<ClassValue>> builtin_classes;
     std::string error_message;
     
     // Main execution loop
diff --git a/tests/test_generic_builtin.cpp b/tests/test_generic_builtin.cpp
new file mode 100644
index 0000000..c7352e3
--- /dev/null
+++ b/tests/test_generic_builtin.cpp
@@ -0,0 +1,59 @@
+#include "camellya.h"
+#include "exceptions.h"
+#include <catch2/catch_all.hpp>
+#include <cmath>
+
+using namespace camellya;
+
+// Simple Vector3D wrapper for testing
+class Vector3DValue : public NativeValue {
+public:
+    double x, y, z;
+    Vector3DValue(double x, double y, double z) : NativeValue("Vector3D"), x(x), y(y), z(z) {}
+    
+    std::string to_string() const override {
+        return "Vector3D(" + std::to_string(x) + ", " + std::to_string(y) + ", " + std::to_string(z) + ")";
+    }
+    
+    ValuePtr clone() const override {
+        return std::make_shared<Vector3DValue>(x, y, z);
+    }
+};
+
+TEST_CASE("Generic built-in class (Vector3D) test", "[generic]") {
+    Camellya c;
+    
+    // 1. Create the ClassValue for Vector3D
+    auto v3d_klass = std::make_shared<ClassValue>("Vector3D");
+    
+    // 2. Add a native method 'length'
+    v3d_klass->add_method("length", std::make_shared<FunctionValue>("length",
+        [](const std::vector<ValuePtr>& args) -> ValuePtr {
+            if (args.size() != 1) throw RuntimeError("Vector3D.length() expects 0 arguments.");
+            auto vec = std::dynamic_pointer_cast<Vector3DValue>(args[0]);
+            double len = std::sqrt(vec->x * vec->x + vec->y * vec->y + vec->z * vec->z);
+            return std::make_shared<NumberValue>(len);
+        }));
+    
+    // 3. Register it as a built-in class for type "Vector3D"
+    c.register_builtin_class("Vector3D", v3d_klass);
+    
+    // 4. Register a factory function to create Vector3D instances from script
+    c.register_function("Vector3D", [](const std::vector<ValuePtr>& args) -> ValuePtr {
+        if (args.size() != 3) throw RuntimeError("Vector3D() expects 3 arguments.");
+        double x = std::dynamic_pointer_cast<NumberValue>(args[0])->value;
+        double y = std::dynamic_pointer_cast<NumberValue>(args[1])->value;
+        double z = std::dynamic_pointer_cast<NumberValue>(args[2])->value;
+        return std::make_shared<Vector3DValue>(x, y, z);
+    });
+
+    SECTION("vector3d methods") {
+        REQUIRE(c.do_string(R"(
+            var v = Vector3D(3, 4, 0);
+            var len = v.length();
+        )"));
+        
+        auto len = c.get_global("len");
+        REQUIRE(std::dynamic_pointer_cast<NumberValue>(len)->value == 5.0);
+    }
+}
diff --git a/tests/test_list.cpp b/tests/test_list.cpp
new file mode 100644
index 0000000..084af77
--- /dev/null
+++ b/tests/test_list.cpp
@@ -0,0 +1,18 @@
+#include "camellya.h"
+#include <catch2/catch_all.hpp>
+
+using namespace camellya;
+TEST_CASE("Basic List test", "[list]") {
+  Camellya c;
+
+  SECTION("len function") {
+    REQUIRE(c.do_string(R"(
+            var arr = [1, 2, 3, 4];
+            var size = len(arr);
+            arr.push(5);
+            size = arr.len();
+        )"));
+    auto size = c.get_global("size");
+    REQUIRE(std::dynamic_pointer_cast<NumberValue>(size)->value == 5.0);
+  }
+}
diff --git a/tests/test_map_builtin.cpp b/tests/test_map_builtin.cpp
new file mode 100644
index 0000000..d937b69
--- /dev/null
+++ b/tests/test_map_builtin.cpp
@@ -0,0 +1,32 @@
+#include "camellya.h"
+#include <catch2/catch_all.hpp>
+
+using namespace camellya;
+
+TEST_CASE("Map built-in class test", "[map]") {
+    Camellya c;
+
+    SECTION("map methods") {
+        REQUIRE(c.do_string(R"(
+            var m = {"a": 1, "b": 2};
+            var s1 = m.len();
+            m.set("c", 3);
+            var s2 = m.len();
+            var has_a = m.has("a");
+            var has_z = m.has("z");
+            var val_b = m.get("b");
+        )"));
+        
+        auto s1 = c.get_global("s1");
+        auto s2 = c.get_global("s2");
+        auto has_a = c.get_global("has_a");
+        auto has_z = c.get_global("has_z");
+        auto val_b = c.get_global("val_b");
+
+        REQUIRE(std::dynamic_pointer_cast<NumberValue>(s1)->value == 2.0);
+        REQUIRE(std::dynamic_pointer_cast<NumberValue>(s2)->value == 3.0);
+        REQUIRE(std::dynamic_pointer_cast<BoolValue>(has_a)->value == true);
+        REQUIRE(std::dynamic_pointer_cast<BoolValue>(has_z)->value == false);
+        REQUIRE(std::dynamic_pointer_cast<NumberValue>(val_b)->value == 2.0);
+    }
+}