diff --git a/perception/simple_object_merger/CMakeLists.txt b/perception/simple_object_merger/CMakeLists.txt
index 10bd0efa7b8fc..71f8d7c668093 100644
--- a/perception/simple_object_merger/CMakeLists.txt
+++ b/perception/simple_object_merger/CMakeLists.txt
@@ -17,9 +17,13 @@ rclcpp_components_register_node(simple_object_merger_node_component
 
 # Tests
 if(BUILD_TESTING)
-  list(APPEND AMENT_LINT_AUTO_EXCLUDE ament_cmake_uncrustify)
-  find_package(ament_lint_auto REQUIRED)
-  ament_lint_auto_find_test_dependencies()
+  file(GLOB_RECURSE test_files test/*.cpp)
+
+  ament_add_ros_isolated_gtest(test_simple_object_merger_node ${test_files})
+
+  target_link_libraries(test_simple_object_merger_node
+    simple_object_merger_node_component
+  )
 endif()
 
 # Package
diff --git a/perception/simple_object_merger/package.xml b/perception/simple_object_merger/package.xml
index 487155bffd102..1f65c3afdc5d3 100644
--- a/perception/simple_object_merger/package.xml
+++ b/perception/simple_object_merger/package.xml
@@ -12,7 +12,9 @@
 
   <buildtool_depend>ament_cmake_auto</buildtool_depend>
 
+  <depend>ament_cmake_ros</depend>
   <depend>autoware_perception_msgs</depend>
+  <depend>autoware_test_utils</depend>
   <depend>autoware_universe_utils</depend>
   <depend>geometry_msgs</depend>
   <depend>rclcpp</depend>
diff --git a/perception/simple_object_merger/src/simple_object_merger_node/simple_object_merger_node.cpp b/perception/simple_object_merger/src/simple_object_merger_node/simple_object_merger_node.cpp
index faa531560ba09..56ca0fa57a571 100644
--- a/perception/simple_object_merger/src/simple_object_merger_node/simple_object_merger_node.cpp
+++ b/perception/simple_object_merger/src/simple_object_merger_node/simple_object_merger_node.cpp
@@ -15,6 +15,7 @@
 #include "simple_object_merger/simple_object_merger_node.hpp"
 
 #include <geometry_msgs/msg/pose_stamped.hpp>
+#include <tf2_geometry_msgs/tf2_geometry_msgs.hpp>
 
 #include <memory>
 #include <string>
diff --git a/perception/simple_object_merger/test/test_simple_object_merger_node.cpp b/perception/simple_object_merger/test/test_simple_object_merger_node.cpp
new file mode 100644
index 0000000000000..d6346b03e625a
--- /dev/null
+++ b/perception/simple_object_merger/test/test_simple_object_merger_node.cpp
@@ -0,0 +1,150 @@
+// Copyright 2024 TIER IV, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "simple_object_merger/simple_object_merger_node.hpp"
+
+#include <ament_index_cpp/get_package_share_directory.hpp>
+#include <autoware_test_utils/autoware_test_utils.hpp>
+
+#include <gtest/gtest.h>
+
+#include <vector>
+
+using autoware_perception_msgs::msg::DetectedObject;
+using autoware_perception_msgs::msg::DetectedObjects;
+using autoware_perception_msgs::msg::ObjectClassification;
+using simple_object_merger::SimpleObjectMergerNode;
+
+std::shared_ptr<autoware::test_utils::AutowareTestManager> generateTestManager()
+{
+  auto test_manager = std::make_shared<autoware::test_utils::AutowareTestManager>();
+  return test_manager;
+}
+
+std::shared_ptr<SimpleObjectMergerNode> generateNode()
+{
+  auto node_options = rclcpp::NodeOptions{};
+  node_options.append_parameter_override("use_sim_time", true);
+  node_options.append_parameter_override("update_rate_hz", 20.0);
+  node_options.append_parameter_override("new_frame_id", "base_link");
+  node_options.append_parameter_override("timeout_threshold", 1.0);
+  node_options.append_parameter_override(
+    "input_topics", std::vector<std::string>{"/input/objects1", "/input/objects2"});
+
+  return std::make_shared<SimpleObjectMergerNode>(node_options);
+}
+
+TEST(SimpleObjectMergerNodeTest, testSimpleObjectMerge)
+{
+  rclcpp::init(0, nullptr);
+  const std::string input_topic_1 = "/input/objects1";
+  const std::string input_topic_2 = "/input/objects2";
+  const std::string output_topic = "/simple_object_merger/output/objects";
+  auto test_manager = generateTestManager();
+  auto test_target_node = generateNode();
+
+  // Create subscriber
+  size_t latest_msg_objects_size = 0;
+  auto callback = [&latest_msg_objects_size](const DetectedObjects::ConstSharedPtr msg) {
+    latest_msg_objects_size = msg->objects.size();
+  };
+  test_manager->set_subscriber<DetectedObjects>(output_topic, callback);
+
+  // Create a DetectedObjects message with one object
+  DetectedObjects msg;
+  msg.header.frame_id = "base_link";
+  {
+    DetectedObject object;
+    object.kinematics.pose_with_covariance.pose.position.x = 10.0;
+    object.kinematics.pose_with_covariance.pose.position.y = 5.0;
+    object.shape.dimensions.x = 1.0;
+    object.shape.dimensions.y = 1.0;
+    object.shape.dimensions.z = 1.0;
+    object.classification.resize(1);
+    object.classification[0].label = ObjectClassification::UNKNOWN;
+    msg.objects.push_back(object);
+  }
+
+  // Set start time
+  auto clock = std::make_shared<rclcpp::Clock>(RCL_ROS_TIME);
+  rclcpp::Time current_time(0, 0, clock->get_clock_type());
+
+  // Publish the message to topic1
+  test_manager->jump_clock(current_time);
+  msg.header.stamp = current_time;
+  test_manager->test_pub_msg<DetectedObjects>(test_target_node, input_topic_1, msg);
+
+  // Increment time for 0.1 sec
+  current_time = current_time + rclcpp::Duration::from_seconds(0.1);  // 0.1 sec
+
+  // Publish the message to topic2
+  test_manager->jump_clock(current_time);
+  msg.header.stamp = current_time;
+  test_manager->test_pub_msg<DetectedObjects>(test_target_node, input_topic_2, msg);
+
+  EXPECT_EQ(latest_msg_objects_size, 2u);
+  rclcpp::shutdown();
+}
+
+TEST(SimpleObjectMergerNodeTest, testSimpleObjectMergeTimeOut)
+{
+  rclcpp::init(0, nullptr);
+  const std::string input_topic_1 = "/input/objects1";
+  const std::string input_topic_2 = "/input/objects2";
+  const std::string output_topic = "/simple_object_merger/output/objects";
+  auto test_manager = generateTestManager();
+  auto test_target_node = generateNode();
+
+  // Create subscriber
+  size_t latest_msg_objects_size = 0;
+  auto callback = [&latest_msg_objects_size](const DetectedObjects::ConstSharedPtr msg) {
+    latest_msg_objects_size = msg->objects.size();
+  };
+  test_manager->set_subscriber<DetectedObjects>(output_topic, callback);
+
+  // Create a DetectedObjects message with one object
+  DetectedObjects msg;
+  msg.header.frame_id = "base_link";
+  {
+    DetectedObject object;
+    object.kinematics.pose_with_covariance.pose.position.x = 10.0;
+    object.kinematics.pose_with_covariance.pose.position.y = 5.0;
+    object.shape.dimensions.x = 1.0;
+    object.shape.dimensions.y = 1.0;
+    object.shape.dimensions.z = 1.0;
+    object.classification.resize(1);
+    object.classification[0].label = ObjectClassification::UNKNOWN;
+    msg.objects.push_back(object);
+  }
+
+  // Set start time
+  auto clock = std::make_shared<rclcpp::Clock>(RCL_ROS_TIME);
+  rclcpp::Time current_time(0, 0, clock->get_clock_type());
+
+  // Publish the message to topic1
+  test_manager->jump_clock(current_time);
+  msg.header.stamp = current_time;
+  test_manager->test_pub_msg<DetectedObjects>(test_target_node, input_topic_1, msg);
+
+  // Increment time for 2.0 sec
+  current_time = current_time + rclcpp::Duration::from_seconds(2.0);  // 2.0 sec
+
+  // Publish the message to topic2
+  test_manager->jump_clock(current_time);
+  msg.header.stamp = current_time;
+  test_manager->test_pub_msg<DetectedObjects>(test_target_node, input_topic_2, msg);
+
+  EXPECT_EQ(latest_msg_objects_size, 1u);
+  rclcpp::shutdown();
+}