Improve unit test coverage for CF_CFDP_CopyStringFromLV

[abnsy]

Checklist (Please check before submitting)

• [v] I reviewed the Contributing Guide.
• I signed and emailed the appropriate Contributor License Agreement to GSFC-SoftwareRelease@mail.nasa.gov and copied cfs-program@lists.nasa.gov.

This contribution improves unit test coverage for CF_CFDP_CopyStringFromLV().

Additional test cases were added to verify existing error handling paths, including:

Destination buffer too small
NULL source logical value pointer
NULL destination buffer pointer
Zero-sized destination buffer
NULL source data pointer with non-zero length

No production code changes are included.

Fixes: N/A

Testing performed

Updated unit-test/cf_cfdp_tests.c
Executed unit tests
Verified successful build and test execution

Expected behavior changes

API Change: None
Behavior Change: None
Impact: No operational impact. This change only improves unit test coverage for existing validation logic.

System(s) tested on

Hardware: PC
OS: Windows 11
Versions:
CF current development branch
Git for Windows
VS Code

Additional context

The new test cases exercise existing defensive input validation paths that were previously not explicitly covered by unit tests.

Third party code

None.

Contributor Info - All information REQUIRED for consideration of pull request

Full name: Albern Surya Adi

Organization: Personal