Enhancement: Add comprehensive test cases to ensure the robustness of the Variant-Linker tool.

[berntpopp]

Current Behavior

The tool lacks comprehensive test cases, which can lead to undetected bugs and regressions.

Proposed Solution

• Develop a suite of test cases covering various scenarios, including:
  • VCF format variants
  • Non-coding variants
  • Different genome assemblies (hg19/hg38)
  • Specific variants that have caused issues (e.g., ENST00000302118:c.137G>A)
• Use a testing framework such as Jest or Mocha for implementation.

Acceptance Criteria

• [ ] Comprehensive test cases are added to cover various scenarios.
• [ ] Tests are automated and integrated into the CI/CD pipeline.
• [ ] Documentation is updated to guide contributors on running tests.