🐛 Fix exit code 0 even though tests fail

[corytodd]

🍍

Summary

Fix exit code always returning 0 on test failure when no reporting plugin is active.

#1112: Exit code is determined by whether an active reporting plugin passed a block to run_report returning a
non-empty failure string. With no stdout plugin configured, register_build_failure was never called and the build
silently exited 0. Fix moves failure detection into post_test_fixture_execute, which fires regardless of plugin configuration.

process_and_write_results returned :result (singular) but generator.rb read it as :results, so result counts were
always nil at post_test_fixture_execute. Fixed at the source in generator_test_results.rb for consistency with the rest
of the codebase.

Workaround

Active reporting plugins still register failures via their block, producing duplicate banner entries
alongside the core registration. Deduplicated in print_plugin_failures with .uniq. A cleaner fix would split run_report's
dual responsibilities but that is a breaking plugin API change.

Testing

Verified against examples/temp_sensor with a manually broken assertion in TestMain.c and the removal of report_tests_pretty_stdout from enabled plugins.

• Before this patch, the failed test produces a return code of 0.
• After this patch, the failed test produces a return code of 1.

With report_tests_pretty_stdout enabled, we still see exit 1 just as before and there are no duplicated banner messages. All new and current tests are passing . Robucop doesn't seem offended by anything in this patch set.

Resolves #1112

[corytodd]

My thinking here is that graceful_fail should be used by plugins that want to force an exit 0. However, I'm a little worried that we may see failures for plugins or configurations that were depending on this implicit exit code discard behavior.

[mkarlesky]

This is good work, @corytodd. Thank you!

[mkarlesky]

Alas, the plugin architecture has always been a bit rickety. This is more evidence that it needs a proper rethink (coincident with finishing replacing Rake entirely).