Improve risk-driven test coverage

[han-xudong]

Summary

• cover unconnected, send, poll, receive, timeout saturation, and reconnect paths in the POSIX UDP transport
• add CLI process-boundary smoke tests that assert exit codes without coupling tests to output wording
• keep production code, public APIs, coverage exclusions, and thresholds unchanged

Coverage

Metric	Before	After
Local line coverage	86.8%	87.9%
Local branch coverage	78.3%	80.2%
POSIX transport line coverage	81.1%	92.2%
POSIX transport branch coverage	67.1%	91.4%
CLI main line coverage	60.0%	85.0%

Verification

• pixi run format-check
• pixi run test (13/13 tests)
• pixi run coverage (line gate >= 85%)
• pixi run -e cmake-316 cmake-316-test
• transport RED: send failure tests failed before enabling the linker wrappers
• CLI RED: CTest reported no matching tests before process tests were registered

Summary by CodeRabbit

• Tests
  • Expanded POSIX transport test coverage for interrupted operations, send/receive failures, invalid descriptors, timeouts, and datagram payload sizing.
  • Added a shared mechanism to validate program exit codes in test runs.
• CLI
  • Improved automated checks for --help and invalid commands, ensuring consistent and correct exit codes.

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Review details

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 700f284d-4805-4723-ba66-fa03293a7257

📥 Commits

Reviewing files that changed from the base of the PR and between db75a66 and 35ad5dc.

📒 Files selected for processing (1)

• test/assert_exit_code.cmake

📝 Walkthrough

Walkthrough

The test suite adds configurable POSIX transport wrappers for poll, send, and receive behavior, expands transport edge-case coverage, and introduces CTest checks for CLI help and invalid-command exit codes.

Changes

Test coverage expansion

Layer / File(s)	Summary
POSIX transport behavior harness test/test_posix_transport.cpp, test/CMakeLists.txt	Adds configurable poll, send, and receive wrappers and links the additional wrapped symbols.
POSIX transport scenarios test/test_posix_transport.cpp	Covers I/O ordering, failures, polling errors, interrupted receives, payload handling, and timeout clamping.
CLI exit-code validation test/assert_exit_code.cmake, test/CMakeLists.txt	Adds reusable process exit-code validation and tests CLI help and invalid-command statuses.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

• netft/netft-cpp#8: Modifies the same __wrap_poll logic for EINTR and expired-deadline behavior.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: broader risk-driven test coverage without production-code changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch test/risk-driven-coverage

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[coderabbitai]

🧹 Nitpick comments (1)

test/assert_exit_code.cmake (1)

5-16: 🩺 Stability & Availability | 🔵 Trivial | ⚡ Quick win

Harden the process-boundary helper against hangs and launch failures.

A hung CLI can block CTest indefinitely because execute_process() has no timeout. Also, RESULT_VARIABLE may contain a launch-error string rather than an integer, so handle that case explicitly before comparing exit codes.

Proposed fix

 execute_process(
   COMMAND "${PROGRAM}" ${ARGUMENTS}
+  TIMEOUT 30
   RESULT_VARIABLE actual_exit_code
   OUTPUT_QUIET
   ERROR_QUIET
 )
 
+if(NOT actual_exit_code MATCHES "^-?[0-9]+$")
+  message(FATAL_ERROR
+    "Failed to execute ${PROGRAM}: ${actual_exit_code}"
+  )
+endif()
+
 if(NOT actual_exit_code EQUAL EXPECTED_EXIT_CODE)

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@test/assert_exit_code.cmake` around lines 5 - 16, Update the execute_process
call in the assert_exit_code helper to enforce a finite timeout, and validate
actual_exit_code before comparing it with EXPECTED_EXIT_CODE because launch
failures may produce a non-numeric error string. Report launch failures and
timeout results through the existing FATAL_ERROR path while preserving the
current successful exit-code comparison.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@test/assert_exit_code.cmake`:
- Around line 5-16: Update the execute_process call in the assert_exit_code
helper to enforce a finite timeout, and validate actual_exit_code before
comparing it with EXPECTED_EXIT_CODE because launch failures may produce a
non-numeric error string. Report launch failures and timeout results through the
existing FATAL_ERROR path while preserving the current successful exit-code
comparison.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 5f7459f0-5ed2-438c-9152-244974c50397

📥 Commits

Reviewing files that changed from the base of the PR and between c582769 and 1aadc4c.

📒 Files selected for processing (3)

• test/CMakeLists.txt
• test/assert_exit_code.cmake
• test/test_posix_transport.cpp