add new test messages for arrays of arrays

[Karsten1987]

We'd like to have two more test messages in the form of containers of containers. We would leverage them in our rosbag tests.

see ros2/rosbag2#56 (comment)
cc @anhosi

[jacobperron]

There are some consequences to adding new messages to this package:

1. It will cause test_communications to fail, unless a few things are updated.
   See my tickets related to previous tribulations:

• Add message fixture for DynamicArrayStaticArrayPrimitivesNested #45
• Add new test message type DynamicArrayStaticArrayPrimitivesNested system_tests#302

2. The build time increases significantly for all builds (exponential?) because of testing done in test_communications.
   (@clalancette Correct me if I'm wrong).

[Karsten1987]

Comments make sense to me, but I'll let @anhosi respond.

If this doesn't get merged because of runtime reasons, we might have our own rosbag2_test_msgs paket. But i'd prefer not to.

[jacobperron]

IMO, it makes sense to add the missing cases to this package for completeness:

• BoundedArrayPrimitivesNested
• StaticArrayPrimitivesNested

[Karsten1987]

I just updated the message files. Is there anything else to do with it in terms of test_communication?

[jacobperron]

I just updated the message files. Is there anything else to do with it in terms of test_communication?

@Karsten1987
Support should be added for the new message types to the utility functions in this package:

• message_fixtures.py
• message_fixtures.hpp

And then the publisher/subscriber tests in test_communications should be updated:

• https://github.com/ros2/system_tests/blob/5267cdd2ff2bb40adcee02e28f2c13901e51b6a2/test_communication/test/test_subscriber.cpp#L105
• https://github.com/ros2/system_tests/blob/5267cdd2ff2bb40adcee02e28f2c13901e51b6a2/test_communication/test/test_publisher_subscriber.cpp#L135
• https://github.com/ros2/system_tests/blob/5267cdd2ff2bb40adcee02e28f2c13901e51b6a2/test_communication/test/test_publisher.cpp#L73

An alternative to all of these changes is to let the publisher/subscriber tests in test_communications pass if the message type is unknown. Then any future additions to test_msgs wouldn't break integration tests. I.e. Return 0 here and the same for the other test I've linked.

[Karsten1987]

• Linux
• Linux-aarch64
• macOS
• Windows

[Karsten1987]

new round of CI:

• Linux
• Linux-aarch64
• macOS
• Windows