Tests on Windows falsely positive reporting passed due to SIGINT handling

Bug report

Required Info:

• Operating System: Windows
• Installation type: Binary through Robostack/ms-iot
• Version or commit hash: humble
• DDS implementation: the default bundled one
• Client library (if applicable): rclcpp

Steps to reproduce issue

1. Write a launch file in Python to launch one or more nodes.
2. Write a gtest executable (for communication) that exit with code 1.
3. build and test with rostest and launch_testing.asserts.assertExitCodes:

    @pytest.mark.rostest
    def generate_test_description():
        return (
            LaunchDescription(
                [...]
            ),
            {...: ...},
        )
    
    @launch_testing.post_shutdown_test()
    class TestOutcome(unittest.TestCase):
        def test_exit_codes(self, proc_info):
            launch_testing.asserts.assertExitCodes(proc_info)
   

Expected behavior

Failures are reported through assertExitCodes with a non-zero exit code.

Actual behavior

The test passes.

Additional information

This is related to https://github.com/ros2/launch/pull/94 which sends SIGTERM (it is stated that SIGINT is not supported in Windows).
Besides, exit_code=1 is allowed in https://github.com/ros2/launch/blob/d9ffd805e3d9ca42fe4dd0019ae095e9eb0d4d72/launch_testing/launch_testing/asserts/assert_exit_codes.py#L34-L39

Ask for help

• Are there any available workarounds for writing tests on Windows?
• Which component fails to handle SIGINT on Windows: the launch service or ROS2 executors?

@hidmic Do you have some information? (I notice the TODO are assigned to you.)

Start by reproducing the provided launch_testing scenario on Windows and inspect launch_testing/asserts/assert_exit_codes.py, especially the handling of exit_code=1. Trace the SIGINT and SIGTERM behavior referenced in the issue and launch PR #94. Done means a gtest process exiting with code 1 causes assertExitCodes to report a failure rather than passing.