Move test_utils module from demos repo

[christophfroehlich]

As integration testing gets more popular I propose to release the test_utils from the ros2_control_demos repository.

I added it to the controller_manager package to be able to use it in the test for the ros2_control_node.
I had to use ament_cmake_pytest instead of launch_testing_ament_cmake, otherwise the coverage was not evaluated of the python files.

Tested with semi-binary builds of ros-controls/ros2_control_demos#673

[codecov]

Codecov Report

Attention: Patch coverage is 86.95652% with 12 lines in your changes missing coverage. Please review.

Project coverage is 88.24%. Comparing base (65d4092) to head (7bd97e2).
Report is 12 commits behind head on master.

Files with missing lines	Patch %	Lines
...ontroller_manager/controller_manager/test_utils.py	77.35%	8 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1955      +/-   ##
==========================================
+ Coverage   87.73%   88.24%   +0.51%     
==========================================
  Files         122      123       +1     
  Lines       13052    13129      +77     
  Branches     1171     1183      +12     
==========================================
+ Hits        11451    11586     +135     
+ Misses       1169     1093      -76     
- Partials      432      450      +18     

Flag	Coverage Δ
unittests	88.24% <86.95%> (+0.51%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...ller_manager/test/test_ros2_control_node_launch.py	100.00% <100.00%> (ø)
...ontroller_manager/controller_manager/test_utils.py	77.35% <77.35%> (ø)

... and 5 files with indirect coverage changes

[saikishor]

LGTM. A nice addition

[fmauch]

Wasn't that the functionality that was causing trouble for us in the spawner when waiting for the controller manager?

[christophfroehlich]

I'm not sure, I can't remember. I added this some time ago in the demo tests, and it seemed to be useful back then ;) maybe the list_controllers service is now more robust and we could skip this node check in advance.

[saikishor]

Atleast in the ros2_control_demos, we haven't seen flaky tests due to this right?. We can remove it, if this is not interesting for us to have consistency or we can get back to it when we see some flakiness. Both are fine for me

[christophfroehlich]

no it didn't make any problems recently

[saikishor]

I'll approve it as I don't have a strong opinion on this