Check that future is done, and always call rclpy.shutdown

[sloretz]

This partially undoes #270 - I didn't realize spin_until_future_complete() does nothing on timeout, so the future's result could be None. This assert's the future is done before using the result.

The second commit Makes sure rclpy.shutdown() is always called. It looks like all the tests are run in the same Python instance, so the tests need to be extra careful when initializing rclpy globally. Using a try/finally construct makes sure rclpy will be shutdown for the next test. Otherwise, errors like this one can happen: https://ci.ros2.org/job/ci_windows/15536/consoleText

===============================================================================================================================
FAIL: set_param_launch_test.TestFixture.test_set_parameter
-------------------------------------------------------------------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\ci\ws\src\ros2\launch_ros\launch_testing_ros\test\examples\set_param_launch_test.py", line 49, in test_set_parameter
    rclpy.init()
  File "C:\ci\ws\install\Lib\site-packages\rclpy\__init__.py", line 76, in init
    return context.init(args, domain_id=domain_id)
  File "C:\ci\ws\install\Lib\site-packages\rclpy\context.py", line 70, in init
    raise RuntimeError('Context.init() must only be called once')
RuntimeError: Context.init() must only be called once
---------------------------- Captured stdout call -----------------------------
[INFO] [launch]: All log files can be found below C:\Users\ContainerAdministrator\.ros\log\2021-09-30-19-48-41-770984-0cec77497c5b-3144
[INFO] [launch]: Default logging verbosity is set to INFO
[INFO] [python.exe-3]: process started with pid [872]
[WARNING] [python.exe-3]: 'SIGINT' sent to process[python.exe-3] not supported on Windows, escalating to 'SIGTERM'
[INFO] [python.exe-3]: sending signal 'SIGTERM' to process[python.exe-3]
[ERROR] [python.exe-3]: process has died [pid 872, exit code 1, cmd 'C:\Python38\python.exe C:\ci\ws\src\ros2\launch_ros\launch_testing_ros\test\examples\parameter_blackboard.py --ros-args -r __node:=demo_node_1'].
---------------------------- Captured stderr call -----------------------------
test_set_parameter (set_param_launch_test.TestFixture) ... ERROR

======================================================================
ERROR: test_set_parameter (set_param_launch_test.TestFixture)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\ci\ws\src\ros2\launch_ros\launch_testing_ros\test\examples\set_param_launch_test.py", line 51, in test_set_parameter
    response = node.set_parameter(state=True)
  File "C:\ci\ws\src\ros2\launch_ros\launch_testing_ros\test\examples\set_param_launch_test.py", line 75, in set_parameter
    return response.results[0]
AttributeError: 'NoneType' object has no attribute 'results'

[sloretz]

CI (build: --packages-up-to launch_testing_ros test: --packages-select launch_testing_ros)

• Linux
• Linux-aarch64
• macOS
• Windows

[Blast545]

More recent CI, --packages-above-and-dependencies launch_testing_ros

• Linux
• Linux-aarch64
• macOS
• Windows

[Blast545]

As this has been constantly failing in the Windows debug job:

• Windows Debug

[Blast545]

@sloretz I think it's good to go 👍

[sloretz]

Thank you @Blast545 for following up on this with CI!

[Blast545]

👨‍🌾 This extra added assert failed in the windows release nightlies:

launch_ros/launch_testing_ros/test/examples/set_param_launch_test.py

Line 76 in 4bfd998

assert future.done(), 'Client request timed out'

Can I ask you to take a look @sloretz? 🙏
https://ci.ros2.org/view/nightly/job/nightly_win_rel/2086/

[sloretz]

@Blast545 That's expected. The service call in the test has been flaky since #263 - this PR improves the error handling so it doesn't affect other tests.

[Blast545]

Oh, I see. Thanks for the context!

[Blast545]

I don't think it's a flaky call, it has been failing constantly in the past 5 WIndows Release CI jobs. ci.ros2.org/nightly_win_rel#2090/. Can I ask you to take an extra look @sloretz ?