Build:

colcon build -DBUILD_TESTING=1 --packages-select test_hardware

Run:

ros2 launch test_hardware view_1dof.launch.py

Error:

[INFO] [launch]: All log files can be found below /home/user/.ros/log/2024-11-19-16-34-10-761991-Rechenmaschine-6390
[INFO] [launch]: Default logging verbosity is set to INFO
[INFO] [ros2_control_node-1]: process started with pid [6394]
[INFO] [robot_state_publisher-2]: process started with pid [6395]
[INFO] [spawner-3]: process started with pid [6396]
[ros2_control_node-1] [INFO] [1732034050.952412737] [controller_manager]: Subscribing to '/robot_description' topic for robot description.
[ros2_control_node-1] [INFO] [1732034050.952552074] [controller_manager]: update rate is 10 Hz
[ros2_control_node-1] [WARN] [1732034050.952659563] [controller_manager]: Could not enable FIFO RT scheduling policy: with error number <1>(Operation not permitted). See [https://control.ros.org/master/doc/ros2_control/controller_manager/doc/userdoc.html] for details on how to enable realtime scheduling.
[robot_state_publisher-2] [INFO] [1732034050.957780548] [robot_state_publisher]: Robot initialized
[ros2_control_node-1] [INFO] [1732034050.957913809] [controller_manager]: Received robot description from topic.
[ros2_control_node-1] [INFO] [1732034050.959827028] [controller_manager.resource_manager]: Loading hardware 'WheelJoint' 
[ros2_control_node-1] [ERROR] [1732034050.960321658] [controller_manager.resource_manager]: Caught exception of type : N9pluginlib20CreateClassExceptionE while loading hardware: MultiLibraryClassLoader: Could not create class of type test_hardware/TestActuator
[ros2_control_node-1] [WARN] [1732034050.960382632] [controller_manager]: Could not load and initialize hardware. Please check previous output for more details. After you have corrected your URDF, try to publish robot description again.
[spawner-3] [INFO] [1732034051.278139569] [spawner_forward_position_controller]: waiting for service /controller_manager/list_controllers to become available...
[ros2_control_node-1] [WARN] [1732034051.952014765] [controller_manager]: Waiting for data on 'robot_description' topic to finish initialization
[ros2_control_node-1] [WARN] [1732034052.951998904] [controller_manager]: Waiting for data on 'robot_description' topic to finish initialization
[ros2_control_node-1] [WARN] [1732034053.952009371] [controller_manager]: Waiting for data on 'robot_description' topic to finish initialization

Solution from Martin Peris at robotics.stackexchange.com:

ros2_control_hardware_interface_error/test_hardware.xml

Lines 1 to 7 in 0279741

	<library path="test_interface">
	<class name="test_hardware/TestActuator" type="test_hardware/TestActuator" base_class_type="hardware_interface::ActuatorInterface">
	<description>
	Test
	</description>
	</class>
	</library>

Indeed type="test_hardware/TestActuator" should be type=test_hardware::TestActuator In