diff --git a/perception/image_projection_based_fusion/CMakeLists.txt b/perception/image_projection_based_fusion/CMakeLists.txt
index b13f68b07181e..7baed86088811 100644
--- a/perception/image_projection_based_fusion/CMakeLists.txt
+++ b/perception/image_projection_based_fusion/CMakeLists.txt
@@ -160,6 +160,13 @@ else()
   message("Skipping build of some nodes due to missing dependencies")
 endif()
 
+if(BUILD_TESTING)
+  find_package(ament_cmake_gtest REQUIRED)
+  ament_auto_add_gtest(test_utils
+    test/test_utils.cpp
+  )
+endif()
+
 ament_auto_package(INSTALL_TO_SHARE
     launch
     config
diff --git a/perception/image_projection_based_fusion/package.xml b/perception/image_projection_based_fusion/package.xml
index a5b41a30be166..57fe994aedf5a 100644
--- a/perception/image_projection_based_fusion/package.xml
+++ b/perception/image_projection_based_fusion/package.xml
@@ -36,6 +36,7 @@
   <depend>tier4_autoware_utils</depend>
   <depend>tier4_perception_msgs</depend>
 
+  <test_depend>ament_cmake_gtest</test_depend>
   <test_depend>ament_lint_auto</test_depend>
   <test_depend>autoware_lint_common</test_depend>
 
diff --git a/perception/image_projection_based_fusion/test/test_utils.cpp b/perception/image_projection_based_fusion/test/test_utils.cpp
new file mode 100644
index 0000000000000..e578ce1987cc3
--- /dev/null
+++ b/perception/image_projection_based_fusion/test/test_utils.cpp
@@ -0,0 +1,170 @@
+// 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 <autoware_point_types/types.hpp>
+#include <image_projection_based_fusion/utils/utils.hpp>
+
+#include <gtest/gtest.h>
+
+using autoware_point_types::PointXYZI;
+
+void setPointCloud2Fields(sensor_msgs::msg::PointCloud2 & pointcloud)
+{
+  pointcloud.fields.resize(4);
+  pointcloud.fields[0].name = "x";
+  pointcloud.fields[1].name = "y";
+  pointcloud.fields[2].name = "z";
+  pointcloud.fields[3].name = "intensity";
+  pointcloud.fields[0].offset = 0;
+  pointcloud.fields[1].offset = 4;
+  pointcloud.fields[2].offset = 8;
+  pointcloud.fields[3].offset = 12;
+  pointcloud.fields[0].datatype = sensor_msgs::msg::PointField::FLOAT32;
+  pointcloud.fields[1].datatype = sensor_msgs::msg::PointField::FLOAT32;
+  pointcloud.fields[2].datatype = sensor_msgs::msg::PointField::FLOAT32;
+  pointcloud.fields[3].datatype = sensor_msgs::msg::PointField::FLOAT32;
+  pointcloud.fields[0].count = 1;
+  pointcloud.fields[1].count = 1;
+  pointcloud.fields[2].count = 1;
+  pointcloud.fields[3].count = 1;
+  pointcloud.height = 1;
+  pointcloud.point_step = 16;
+  pointcloud.is_bigendian = false;
+  pointcloud.is_dense = true;
+  pointcloud.header.frame_id = "dummy_frame_id";
+  pointcloud.header.stamp.sec = 0;
+  pointcloud.header.stamp.nanosec = 0;
+}
+
+// Test case 1: Test case when the input pointcloud is empty
+TEST(UtilsTest, closest_cluster_empty_cluster_test_case1)
+{
+  sensor_msgs::msg::PointCloud2 pointcloud;
+  setPointCloud2Fields(pointcloud);
+  pointcloud.data.resize(0);
+  pointcloud.width = 0;
+  pointcloud.row_step = 0;
+
+  pcl::PointXYZ center;
+  center.x = 0.0;
+  center.y = 0.0;
+  center.z = 0.0;
+
+  // testing closest_cluster function
+  double cluster_2d_tolerance = 0.5;
+  int min_cluster_size = 3;
+  sensor_msgs::msg::PointCloud2 output_cluster;
+  image_projection_based_fusion::closest_cluster(
+    pointcloud, cluster_2d_tolerance, min_cluster_size, center, output_cluster);
+  EXPECT_EQ(output_cluster.data.size(), std::size_t(0));
+}
+
+// Test case 2: Test case when the input pointcloud as one cluster
+TEST(UtilsTest, closest_cluster_test_case2)
+{
+  sensor_msgs::msg::PointCloud2 pointcloud;
+  setPointCloud2Fields(pointcloud);
+  std::vector<float> dummy_x = {0.0, 0.1, 0.2};
+  pointcloud.data.resize(dummy_x.size() * pointcloud.point_step);
+  size_t global_offset = 0;
+  for (auto x : dummy_x) {
+    PointXYZI point;
+    point.x = x;
+    point.y = 0.0;
+    point.z = 0.0;
+    point.intensity = 0.0;
+    memcpy(&pointcloud.data[global_offset], &point, pointcloud.point_step);
+    global_offset += pointcloud.point_step;
+  }
+  pcl::PointXYZ center;
+  center.x = 0.0;
+  center.y = 0.0;
+  center.z = 0.0;
+
+  // testing closest_cluster function
+  double cluster_2d_tolerance = 0.5;
+  int min_cluster_size = 3;
+  sensor_msgs::msg::PointCloud2 output_cluster;
+  image_projection_based_fusion::closest_cluster(
+    pointcloud, cluster_2d_tolerance, min_cluster_size, center, output_cluster);
+  EXPECT_EQ(output_cluster.data.size(), dummy_x.size() * pointcloud.point_step);
+}
+
+// Test case 3: Test case when the input pointcloud as two clusters
+TEST(UtilsTest, closest_cluster_test_case3)
+{
+  sensor_msgs::msg::PointCloud2 pointcloud;
+  setPointCloud2Fields(pointcloud);
+  std::vector<float> dummy_x = {0.0, 0.1, 0.2, 1.0, 1.1, 1.2, 1.21, 1.22};
+  pointcloud.data.resize(dummy_x.size() * pointcloud.point_step);
+  size_t global_offset = 0;
+  for (auto x : dummy_x) {
+    PointXYZI point;
+    point.x = x;
+    point.y = 0.0;
+    point.z = 0.0;
+    point.intensity = 0.0;
+    memcpy(&pointcloud.data[global_offset], &point, pointcloud.point_step);
+    global_offset += pointcloud.point_step;
+  }
+  pcl::PointXYZ center;
+  center.x = 0.0;
+  center.y = 0.0;
+  center.z = 0.0;
+
+  // testing closest_cluster function
+  double cluster_2d_tolerance = 0.5;
+  int min_cluster_size = 3;
+  sensor_msgs::msg::PointCloud2 output_cluster;
+  image_projection_based_fusion::closest_cluster(
+    pointcloud, cluster_2d_tolerance, min_cluster_size, center, output_cluster);
+  EXPECT_EQ(output_cluster.data.size(), 3 * pointcloud.point_step);
+}
+
+// Test case 4: Test case when the input pointcloud as two clusters
+TEST(UtilsTest, closest_cluster_test_case4)
+{
+  sensor_msgs::msg::PointCloud2 pointcloud;
+  setPointCloud2Fields(pointcloud);
+  std::vector<float> dummy_x = {0.0, 0.1, 1.0, 1.01, 1.1, 1.2, 1.21, 1.22};
+  pointcloud.data.resize(dummy_x.size() * pointcloud.point_step);
+  size_t global_offset = 0;
+  for (auto x : dummy_x) {
+    PointXYZI point;
+    point.x = x;
+    point.y = 0.0;
+    point.z = 0.0;
+    point.intensity = 0.0;
+    memcpy(&pointcloud.data[global_offset], &point, pointcloud.point_step);
+    global_offset += pointcloud.point_step;
+  }
+  pcl::PointXYZ center;
+  center.x = 0.0;
+  center.y = 0.0;
+  center.z = 0.0;
+
+  // testing closest_cluster function
+  double cluster_2d_tolerance = 0.5;
+  int min_cluster_size = 3;
+  sensor_msgs::msg::PointCloud2 output_cluster;
+  image_projection_based_fusion::closest_cluster(
+    pointcloud, cluster_2d_tolerance, min_cluster_size, center, output_cluster);
+  EXPECT_EQ(output_cluster.data.size(), 6 * pointcloud.point_step);
+}
+
+int main(int argc, char ** argv)
+{
+  testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}