system/nxinit: add cmocka unit tests for parser/action/service

[JianyuWang0623]

Summary

• Fix a real bug in init_parse_config_lines(): a dead early continue for a truly-empty line (buf == "\0") skipped the memmove() bookkeeping its sibling whitespace-only-line branch performs, corrupting the remaining-length tracking and silently dropping every subsequent line in that refill chunk. The whitespace-skip loop right below already handles the empty-string case correctly, so the buggy early exit is simply redundant and removed.

• Add a test/ subdirectory (mirroring apps/system/uorb/test/) with cmocka-based unit tests covering the logic most prone to regression in NxInit:

  • init_parse_arguments(): plain/quoted arguments, -- separator vs. --option long options (regression coverage for a previously fixed bug), argv-capacity truncation.
  • init_parse_config_file()/init_parse_config_lines(): section routing, blank/whitespace-only line skipping, unknown-section rejection, over-length line rejection, and a line straddling two read-buffer refills.
  • Action event matching (init_action_parse()/init_action_trigger_event()): exact match, invert (!=), fnmatch wildcards, AND semantics across multiple events per action (needs CONFIG_SYSTEM_NXINIT_ACTION_EVENTS_MAX > 1, skipped rather than failed at the default value of 1).
  • Service conflict detection (init_service_parse()/init_service_check()): duplicate service name rejection, override replacing an earlier duplicate, SERVICE_ARGS_MAX boundary.

  Tests exercise only the existing public parser.h/action.h/service.h API; no production symbols were made non-static. Test sources compile action.c/parser.c/service.c a second time into a separate nxinit_unit_test program, gated behind new CONFIG_SYSTEM_NXINIT_TEST (depends on TESTING_CMOCKA); the default init program is unaffected.

Opened as draft for early review/CI feedback.

Impact

• Users: NO (test-only addition; the parser fix only removes dead/buggy code, no behavior change for well-formed configs).
• Build: adds one new optional Kconfig-gated test target; default build unaffected.
• Hardware: NO.
• Documentation: NO.
• Security: NO.
• Compatibility: NO.

Testing

Build Host: Ubuntu 22.04 LTS x86_64, gcc 13.4.0 (Ubuntu 13.4.0-6ubuntu122ppa2)
Target: sim:citest (nuttx sim config, no cross toolchain needed; NxInit is pure apps-layer logic)

nxstyle/checkpatch.sh pass on all changed files.

Actual nxinit_unit_test runtime output on sim (default Kconfig, ACTION_EVENTS_MAX=1):

nsh> nxinit_unit_test
[==========] nxinit_tests: Running 17 test(s).
[ RUN      ] test_nxinit_parser_arguments_spaces
[       OK ] test_nxinit_parser_arguments_spaces
[ RUN      ] test_nxinit_parser_arguments_quoted
[       OK ] test_nxinit_parser_arguments_quoted
[ RUN      ] test_nxinit_parser_arguments_dashdash_separator
[       OK ] test_nxinit_parser_arguments_dashdash_separator
[ RUN      ] test_nxinit_parser_arguments_long_option
[       OK ] test_nxinit_parser_arguments_long_option
[ RUN      ] test_nxinit_parser_arguments_truncate
[       OK ] test_nxinit_parser_arguments_truncate
[ RUN      ] test_nxinit_parser_config_sections
[       OK ] test_nxinit_parser_config_sections
[ RUN      ] test_nxinit_parser_config_skip_blank_lines
[       OK ] test_nxinit_parser_config_skip_blank_lines
[ RUN      ] test_nxinit_parser_config_unknown_section
[       OK ] test_nxinit_parser_config_unknown_section
[ RUN      ] test_nxinit_parser_config_line_too_long
[       OK ] test_nxinit_parser_config_line_too_long
[ RUN      ] test_nxinit_parser_config_line_crosses_boundary
[       OK ] test_nxinit_parser_config_line_crosses_boundary
[ RUN      ] test_nxinit_action_event_match_exact
[       OK ] test_nxinit_action_event_match_exact
[ RUN      ] test_nxinit_action_event_match_invert
[       OK ] test_nxinit_action_event_match_invert
[ RUN      ] test_nxinit_action_event_match_fnmatch
[       OK ] test_nxinit_action_event_match_fnmatch
[ RUN      ] test_nxinit_action_event_and_semantics
[  SKIPPED ] test_nxinit_action_event_and_semantics
[ RUN      ] test_nxinit_service_duplicate_conflict
[       OK ] test_nxinit_service_duplicate_conflict
[ RUN      ] test_nxinit_service_override_replaces_duplicate
[       OK ] test_nxinit_service_override_replaces_duplicate
[ RUN      ] test_nxinit_service_args_max_boundary
[       OK ] test_nxinit_service_args_max_boundary
[==========] nxinit_tests: 17 test(s) run.
[  PASSED  ] 16 test(s).
[  SKIPPED ] nxinit_tests: 1 test(s), listed below:
[  SKIPPED ] test_nxinit_action_event_and_semantics

With CONFIG_SYSTEM_NXINIT_ACTION_EVENTS_MAX=4, test_nxinit_action_event_and_semantics runs and passes (17/17 PASSED), confirming the AND-semantics test is not dead code.

Both commits were re-verified by git cherry-pick-ing directly onto current apache/master (zero conflicts) before opening this PR, since they were originally authored on a branch that has since been squash-merged upstream via #3750.