diff --git a/joint_trajectory_controller/test/test_trajectory_controller.cpp b/joint_trajectory_controller/test/test_trajectory_controller.cpp
index 60b6d44798..ffff98fb7b 100644
--- a/joint_trajectory_controller/test/test_trajectory_controller.cpp
+++ b/joint_trajectory_controller/test/test_trajectory_controller.cpp
@@ -106,77 +106,20 @@ TEST_P(TrajectoryControllerTestParameterized, check_interface_names)
   const auto state = traj_controller_->get_node()->configure();
   ASSERT_EQ(state.id(), State::PRIMARY_STATE_INACTIVE);
 
-  std::vector<std::string> state_interface_names;
-  state_interface_names.reserve(joint_names_.size() * state_interface_types_.size());
-  for (const auto & joint : joint_names_)
-  {
-    for (const auto & interface : state_interface_types_)
-    {
-      state_interface_names.push_back(joint + "/" + interface);
-    }
-  }
-  auto state_interfaces = traj_controller_->state_interface_configuration();
-  EXPECT_EQ(state_interfaces.type, controller_interface::interface_configuration_type::INDIVIDUAL);
-  EXPECT_EQ(state_interfaces.names.size(), joint_names_.size() * state_interface_types_.size());
-  ASSERT_THAT(state_interfaces.names, testing::UnorderedElementsAreArray(state_interface_names));
-
-  std::vector<std::string> command_interface_names;
-  command_interface_names.reserve(joint_names_.size() * command_interface_types_.size());
-  for (const auto & joint : joint_names_)
-  {
-    for (const auto & interface : command_interface_types_)
-    {
-      command_interface_names.push_back(joint + "/" + interface);
-    }
-  }
-  auto command_interfaces = traj_controller_->command_interface_configuration();
-  EXPECT_EQ(
-    command_interfaces.type, controller_interface::interface_configuration_type::INDIVIDUAL);
-  EXPECT_EQ(command_interfaces.names.size(), joint_names_.size() * command_interface_types_.size());
-  ASSERT_THAT(
-    command_interfaces.names, testing::UnorderedElementsAreArray(command_interface_names));
+  compare_joints(joint_names_, joint_names_);
 }
 
 TEST_P(TrajectoryControllerTestParameterized, check_interface_names_with_command_joints)
 {
   rclcpp::executors::MultiThreadedExecutor executor;
-  // set command_joints parameter
+  // set command_joints parameter different than joint_names_
   const rclcpp::Parameter command_joint_names_param("command_joints", command_joint_names_);
   SetUpTrajectoryController(executor, {command_joint_names_param});
 
   const auto state = traj_controller_->get_node()->configure();
   ASSERT_EQ(state.id(), State::PRIMARY_STATE_INACTIVE);
 
-  std::vector<std::string> state_interface_names;
-  state_interface_names.reserve(joint_names_.size() * state_interface_types_.size());
-  for (const auto & joint : joint_names_)
-  {
-    for (const auto & interface : state_interface_types_)
-    {
-      state_interface_names.push_back(joint + "/" + interface);
-    }
-  }
-  auto state_interfaces = traj_controller_->state_interface_configuration();
-  EXPECT_EQ(state_interfaces.type, controller_interface::interface_configuration_type::INDIVIDUAL);
-  EXPECT_EQ(state_interfaces.names.size(), joint_names_.size() * state_interface_types_.size());
-  ASSERT_THAT(state_interfaces.names, testing::UnorderedElementsAreArray(state_interface_names));
-
-  std::vector<std::string> command_interface_names;
-  command_interface_names.reserve(command_joint_names_.size() * command_interface_types_.size());
-  for (const auto & joint : command_joint_names_)
-  {
-    for (const auto & interface : command_interface_types_)
-    {
-      command_interface_names.push_back(joint + "/" + interface);
-    }
-  }
-  auto command_interfaces = traj_controller_->command_interface_configuration();
-  EXPECT_EQ(
-    command_interfaces.type, controller_interface::interface_configuration_type::INDIVIDUAL);
-  EXPECT_EQ(
-    command_interfaces.names.size(), command_joint_names_.size() * command_interface_types_.size());
-  ASSERT_THAT(
-    command_interfaces.names, testing::UnorderedElementsAreArray(command_interface_names));
+  compare_joints(joint_names_, command_joint_names_);
 }
 
 /**
@@ -186,7 +129,7 @@ TEST_P(
   TrajectoryControllerTestParameterized, check_interface_names_with_command_joints_less_than_dof)
 {
   rclcpp::executors::MultiThreadedExecutor executor;
-  // set command_joints parameter
+  // set command_joints parameter to a subset of joint_names_
   std::vector<std::string> command_joint_names{joint_names_[0], joint_names_[1]};
   const rclcpp::Parameter command_joint_names_param("command_joints", command_joint_names);
   SetUpTrajectoryController(executor, {command_joint_names_param});
@@ -194,36 +137,7 @@ TEST_P(
   const auto state = traj_controller_->get_node()->configure();
   ASSERT_EQ(state.id(), State::PRIMARY_STATE_INACTIVE);
 
-  std::vector<std::string> state_interface_names;
-  state_interface_names.reserve(joint_names_.size() * state_interface_types_.size());
-  for (const auto & joint : joint_names_)
-  {
-    for (const auto & interface : state_interface_types_)
-    {
-      state_interface_names.push_back(joint + "/" + interface);
-    }
-  }
-  auto state_interfaces = traj_controller_->state_interface_configuration();
-  EXPECT_EQ(state_interfaces.type, controller_interface::interface_configuration_type::INDIVIDUAL);
-  EXPECT_EQ(state_interfaces.names.size(), joint_names_.size() * state_interface_types_.size());
-  ASSERT_THAT(state_interfaces.names, testing::UnorderedElementsAreArray(state_interface_names));
-
-  std::vector<std::string> command_interface_names;
-  command_interface_names.reserve(command_joint_names.size() * command_interface_types_.size());
-  for (const auto & joint : command_joint_names)
-  {
-    for (const auto & interface : command_interface_types_)
-    {
-      command_interface_names.push_back(joint + "/" + interface);
-    }
-  }
-  auto command_interfaces = traj_controller_->command_interface_configuration();
-  EXPECT_EQ(
-    command_interfaces.type, controller_interface::interface_configuration_type::INDIVIDUAL);
-  EXPECT_EQ(
-    command_interfaces.names.size(), command_joint_names.size() * command_interface_types_.size());
-  ASSERT_THAT(
-    command_interfaces.names, testing::UnorderedElementsAreArray(command_interface_names));
+  compare_joints(joint_names_, command_joint_names);
 }
 
 TEST_P(
diff --git a/joint_trajectory_controller/test/test_trajectory_controller_utils.hpp b/joint_trajectory_controller/test/test_trajectory_controller_utils.hpp
index 09f36d21fe..630dc4d948 100644
--- a/joint_trajectory_controller/test/test_trajectory_controller_utils.hpp
+++ b/joint_trajectory_controller/test/test_trajectory_controller_utils.hpp
@@ -540,6 +540,47 @@ class TrajectoryControllerTest : public ::testing::Test
     }
   }
 
+  /**
+   * @brief compares the joint names and interface types of the controller with the given ones
+   */
+  void compare_joints(
+    std::vector<std::string> state_joint_names, std::vector<std::string> command_joint_names)
+  {
+    std::vector<std::string> state_interface_names;
+    state_interface_names.reserve(state_joint_names.size() * state_interface_types_.size());
+    for (const auto & joint : state_joint_names)
+    {
+      for (const auto & interface : state_interface_types_)
+      {
+        state_interface_names.push_back(joint + "/" + interface);
+      }
+    }
+    auto state_interfaces = traj_controller_->state_interface_configuration();
+    EXPECT_EQ(
+      state_interfaces.type, controller_interface::interface_configuration_type::INDIVIDUAL);
+    EXPECT_EQ(
+      state_interfaces.names.size(), state_joint_names.size() * state_interface_types_.size());
+    ASSERT_THAT(state_interfaces.names, testing::UnorderedElementsAreArray(state_interface_names));
+
+    std::vector<std::string> command_interface_names;
+    command_interface_names.reserve(command_joint_names.size() * command_interface_types_.size());
+    for (const auto & joint : command_joint_names)
+    {
+      for (const auto & interface : command_interface_types_)
+      {
+        command_interface_names.push_back(joint + "/" + interface);
+      }
+    }
+    auto command_interfaces = traj_controller_->command_interface_configuration();
+    EXPECT_EQ(
+      command_interfaces.type, controller_interface::interface_configuration_type::INDIVIDUAL);
+    EXPECT_EQ(
+      command_interfaces.names.size(),
+      command_joint_names.size() * command_interface_types_.size());
+    ASSERT_THAT(
+      command_interfaces.names, testing::UnorderedElementsAreArray(command_interface_names));
+  }
+
   std::string controller_name_;
 
   std::vector<std::string> joint_names_;