Fix the teardown of the controller tests (backport #2183) (#2186)

Author: mergify[bot]

diff_drive_controller/test/test_diff_drive_controller.cpp

@@ -101,6 +101,15 @@ class TestDiffDriveController : public ::testing::Test
       controller_name + "/cmd_vel", rclcpp::SystemDefaultsQoS());
   }
 
+  void TearDown() override
+  {
+    // Reset the controller before the fixture is destroyed to ensure the controller's
+    // shutdown transition (which clears loaned interfaces) runs while the underlying
+    // StateInterface/CommandInterface objects are still alive. LoanedStateInterface stores
+    // a const reference (not a shared_ptr), so destruction order matters.
+    controller_.reset();
+  }
+
   static void TearDownTestCase() { rclcpp::shutdown(); }
 
   /// Publish velocity msgs

omni_wheel_drive_controller/test/test_omni_wheel_drive_controller.hpp

@@ -99,6 +99,15 @@ class OmniWheelDriveControllerFixture : public ::testing::Test
         "/test_omni_wheel_drive_controller/cmd_vel", rclcpp::SystemDefaultsQoS());
   }
 
+  void TearDown() override
+  {
+    // Reset the controller before the fixture is destroyed to ensure the controller's
+    // shutdown transition (which clears loaned interfaces) runs while the underlying
+    // StateInterface/CommandInterface objects are still alive. LoanedStateInterface stores
+    // a const reference (not a shared_ptr), so destruction order matters.
+    controller_.reset();
+  }
+
   static void TearDownTestCase() { rclcpp::shutdown(); }
 
 protected: