Mobly exits with status code 0 after TestAbortAll

[puradox]

If a test executed by test_runner raises signals.TestAbortAll before any failures or errors are received, the test will exit with status code 0 instead of what I expected to be 1. This is due to not executing ok = False

mobly/mobly/test_runner.py

Lines 71 to 87 in 991ecb2

	ok = True
	for config in test_configs:
	runner = TestRunner(
	log_dir=config.log_path, testbed_name=config.testbed_name
	)
	with runner.mobly_logger(console_level=console_level):
	runner.add_test_class(config, test_class, tests)
	try:
	runner.run()
	ok = runner.results.is_all_pass and ok
	except signals.TestAbortAll:
	pass
	except Exception:
	logging.exception('Exception when executing %s.', config.testbed_name)
	ok = False
	if not ok:
	sys.exit(1)

To make this more confusing, if a test failure or error is experienced before TestAbortAll is raised, the test will exit with status code 1.

I believe both of these behaviors oppose most users' expectations of the implication of aborting a test. I would expect the test to always return status code 1 whenever an abort occurs. WDYT about adding ok = False to the except signals.TestAbortAll statement?

At the very least, some doc comments above each signal type would be valuable for setting expectations.