Feat read with read fails

[NestorDP]

Summary

• Implement new test for read function return a errno

Changes

• API changes
• Behavior changes
• Docs updated
• Tests added/updated

Details

• Crete function pointers to allow mook the ::poll and ::read functions

How to test

Screenshots/Logs (optional)

Checklist

• Builds locally (Release + Debug)
• All tests pass (if applicable)
• Lint/format pass: make cppcheck / make cpplint / make uncrustify
• Example(s) tested (if touched)
• Documentation updated (README/docs)

Risks and rollbacks

[Copilot]

Pull Request Overview

This PR introduces testing infrastructure to verify error handling in the read function by allowing system call injection, and improves error message clarity across the codebase.

• Adds function pointer members (poll_, read_) to enable mocking system calls for testing
• Implements new test ReadWithReadFail that verifies proper error handling for various errno values
• Updates existing error messages for consistency and clarity (e.g., "100ms" → "100 milliseconds")

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
include/libserial/serial.hpp	Adds function pointer members and test helper method to inject mock system calls
src/serial.cpp	Replaces direct system calls with function pointers and improves error message formatting
test/test_serial_pty.cpp	Adds comprehensive error scenario testing and replaces log statements with assertions
test/test_ports.cpp	Removes unnecessary logging statement

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[codecov]

Codecov Report

❌ Patch coverage is 88.38710% with 18 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
test/test_serial_pty.cpp	85.21%	17 Missing ⚠️
src/serial.cpp	96.55%	1 Missing ⚠️

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[Copilot]

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 7 comments.

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