fix for plugin tests

[christian-rauch]

I know you seem to have fixed your issue with newer packages. But I think this is not the real solution.

I encountered the same issue on an up-to-date humble installation and found the following. I am just mentioning this here, since some of your branches mention in the README that the problem was fixed by upgrading packages, but there are actually still other steps involved. I hope this helps others who encounter the same issue.

Missing dependency on hardware_interface_testing

First, I got:

C++ exception with description "According to the loaded plugin descriptions the class test_actuator with base class type hardware_interface::ActuatorInterface does not exist. Declared types are  test_hardware_components/TestSingleJointActuator" thrown in the test body.

The test_actuator is defined in hardware_interface_testing:
https://github.com/ros-controls/ros2_control/blob/1d67297e5472ca868bd16f6441ab52bedde66e80/hardware_interface_testing/test/test_components/test_components.xml#L3-L7

So a sudo apt install ros-humble-hardware-interface-testing fixed that issue, but it should still be added to the package.xml as <test_depend>hardware_interface_testing</test_depend>.

Macro PLUGINLIB_EXPORT_CLASS called inside dz_minimal_controller namespace

The next issue was a symbol lookup issue.

[...]/build/dz_minimal_controller/test_load_dz_minimal_controller: symbol lookup error: [...]/install/dz_minimal_controller/lib/libdz_minimal_controller.so: undefined symbol: _ZN21dz_minimal_controller12class_loader4impl30getCurrentlyLoadingLibraryNameB5cxx11Ev

_ZN21dz_minimal_controller12class_loader4impl30getCurrentlyLoadingLibraryNameB5cxx11Ev demangles to:

c++filt _ZN21dz_minimal_controller12class_loader4impl30getCurrentlyLoadingLibraryNameB5cxx11Ev
dz_minimal_controller::class_loader::impl::getCurrentlyLoadingLibraryName[abi:cxx11]()

It's a bit weird that the class_loader should be in the dz_minimal_controller namespace and indeed on the main branch the PLUGINLIB_EXPORT_CLASS macro is called inside the dz_minimal_controller namespace:

dz_minimal_controller/src/dz_minimal_controller.cpp

Lines 119 to 128 in 572716e

	#include "pluginlib/class_list_macros.hpp"
	PLUGINLIB_EXPORT_CLASS(
	dz_minimal_controller::DzMinimalController, controller_interface::ControllerInterface)
	} // namespace dz_minimal_controller

and moving it out of the namespace, like on the dz/cargo-cult-admittance-cmake branch:

dz_minimal_controller/src/dz_minimal_controller.cpp

Lines 122 to 127 in cd5dfc2

	} // namespace dz_minimal_controller
	#include "pluginlib/class_list_macros.hpp"
	PLUGINLIB_EXPORT_CLASS(
	dz_minimal_controller::DzMinimalController, controller_interface::ControllerInterface)

eventually fixes the issue.

I can then call

colcon test --event-handlers=console_direct+

and finally get

100% tests passed, 0 tests failed out of 1

[danzimmerman]

Thanks for the info. I haven't run this for a while and will take a look at and fix the main branch accordingly.