[ros2bag test_record] Gets rid of time.sleep and move to using command.wait_for_output

[jaisontj]

Tries to fix #454

Looks to me that the original problem described at #454 was probably addressed by #466
However, before #466, there was #462 which moved from using different temp directory per test to using one temp directory for all the tests - this PR also introduced the time.sleep within each test and also one within the cleanup block (which deletes the temp directory)

In this PR:

• I've moved from using time.sleep within each tests to using bag_command.wait_for_output which essentially waits for the given timeout number or seconds for the expected output. This waiting needs to be done one way or another to give the process enough time to execute and print whatever it needs to.
• I've also improved on the test conditions. For eg: test_qos_simple and test_incomplete_qos_profile were only testing if the bag_command.output was NOT of the format [ERROR] [ros2bag]. This causes a bug where the test will pass even if bag_command.output is empty ~ which can happen if the process is exited immediately i.e replace time.sleep(3) with a pass

[jaisontj]

Each of the tests can also be reduced to:

 def test_nonexistent_qos_profile(self):
        profile_path = PROFILE_PATH / 'foobar.yaml'
        output_path = Path(self.tmpdir.name) / 'ros2bag_test_nonexistent'
        arguments = ['record', '-a', '--qos-profile-overrides-path', profile_path.as_posix(),
                     '--output', output_path.as_posix()]
        expected_string_regex = re.compile(
            r'ros2 bag record: error: argument --qos-profile-overrides-path: can\'t open')
        with self.launch_bag_command(arguments=arguments) as bag_command:
            condition_result = bag_command.wait_for_output(
                condition=lambda output: expected_string_regex.search(output) is not None,
                timeout=5)
            assert condition_result, print('ros2bag CLI did not produce the expected output')
        bag_command.wait_for_shutdown(timeout=5)
        assert bag_command.terminated
        assert bag_command.exit_code != launch_testing.asserts.EXIT_OK

However, this can have an edge case where wait_for_command gets called after the expected string is printed out.

[dabonnie]

Were you able to run the tests repeatedly by any chance?

[jaisontj]

Were you able to run the tests repeatedly by any chance?

I've been testing on windows using: colcon test --packages-select ros2bag --retest-until-fail 25 --merge-install

[jaisontj]

Looks like the build failure on Rpr__rosbag2__ubuntu_focal_amd64 is unrelated to this PR as the associated tests have passed: http://build.ros2.org/job/Rpr__rosbag2__ubuntu_focal_amd64/206/console#console-section-5

[jaisontj]

Running on CI:

• Linux
• Linux-aarch64
• macOS
• Windows

[jaisontj]

CI On windows with --retest-until-fail 25

• Windows

[jaisontj]

Do note that I was unable to get rid of the time.sleep here as this hack seems to be required.

[emersonknapp]

LGTM!