Refactor test helpers in test-reader-parser.cpp and test-buffer-parser.cpp to use common/shared utilities

[coderabbitai]

Description

Both test-reader-parser.cpp and test-buffer-parser.cpp contain nearly identical test helper functions and data structures that should be refactored into a common/shared test utility module.

Duplicated Code

Shared Data Structures

Both files define:

• CapturePositions struct
• ExpectedToken struct
• ExpectedEvent struct

Shared Helper Functions

Both files implement:

• parse_and_validate() - validates parsed events against expected tokens and captures (with parser-specific differences)
• serialize_id_symbol_map() - serializes the id-to-symbol map (identical implementation)

Proposed Refactoring

1. Create a common test utilities header/source file (e.g., tests/common/test-parser-helpers.hpp).
2. Move the shared data structures to the common utility.
3. Extract the common validation logic from parse_and_validate() into reusable helper functions.
4. Use templates or function overloading to handle parser-specific differences (BufferParser vs ReaderParser).
5. Move serialize_id_symbol_map() to the common utility.

Benefits

• Reduces code duplication
• Easier maintenance when validation logic needs to be updated
• Promotes consistency across test files
• Simplifies adding new parser test files in the future

References

• PR: test: Add unit-tests for ReaderParser (fixes #183). #184
• Comment: test: Add unit-tests for ReaderParser (fixes #183). #184 (comment)
• Requested by: @davidlion