Fix flakiness in reliability tests (test_reliability_4)

[EugenioCollado]

This PR improves the robustness of test_reliability_no_losses to resolve intermittent failures observed in test_reliability_4.

Changes include:

• Added a retry mechanism to explicitly wait for samples if they are not immediately found in the buffer, fixing timing-related flakiness.

• Added safer checks for None to prevent potential execution errors when parsing process output.

[angelrti]

probably we should replace this function with another one that relies on an increasing sample size (-z 0). I've developed that in a different branch: https://github.com/omg-dds/dds-rtps/blob/add_new_test_python_0725/test_suite_functions.py#L356
Used: https://github.com/omg-dds/dds-rtps/blob/add_new_test_python_0725/test_suite.py#L190
It also works with only 1 instance.

It is simpler and less error-prone

[angelrti]

this shouldn't be needed because whenever we call this function, we have already matched a sample (from the interoperability_report.py)

[EugenioCollado]

probably we should replace this function with another one that relies on an increasing sample size (-z 0). I've developed that in a different branch: https://github.com/omg-dds/dds-rtps/blob/add_new_test_python_0725/test_suite_functions.py#L356 Used: https://github.com/omg-dds/dds-rtps/blob/add_new_test_python_0725/test_suite.py#L190 It also works with only 1 instance.

It is simpler and less error-prone

Agreed, this looks like a better solution. I’ll close this PR in favor of yours. Please make sure to use the new check_function in test_reliability_4, and consider removing the other one as well.

[angelrti]

Yes, I will change that