Current unit tests are not updated.

Goal:

Implement unit tests for:

• ExternalDepsInput
• MethodInvocationsTool
• GetCFGTool
• ReadDocsTool
• FileStructureTool
• ReadFileTool
• ReadDiffTool
• PackageRelationsTool
• CodeReferenceReader
• CodeStructureTool

This is not just a test writting Issue. We need to add infrastructure which will run these tests with parameters:

• the tests have to be generic enough to be parameterized
• the parameters have to be something like technology (TypeScript, Python, etc.) and repository (CodeBoarding, PyTorch, Angular, Vue, etc)
• should be easily expandable when we add support for new technologies.