test: add unit tests for gcode/history.py (fixes #66)

[HeaTTap]

Fixes #66

Description

Adds a comprehensive unit test suite in tests/test_history.py for gcode/history.py, covering persistence operations, path sanitization, and error handling.

Key Test Cases Included

• test_path_sanitization: Verifies session name sanitization replacing unsafe characters.
• test_save_and_load_round_trip: Verifies saving and reloading LangChain message instances (SystemMessage, HumanMessage, AIMessage).
• test_save_and_load_tool_call_round_trip: Verifies tool-call → ToolMessage pairing survives a save/load round-trip.
• test_save_and_load_default_session: Verifies default session loading and saving.
• test_load_missing_file: Verifies returning None when no session file exists.
• test_load_corrupt_json & test_load_invalid_message_dict: Verifies returning None gracefully on malformed JSON or invalid schema.
• test_clear_session & test_clear_default_session: Verifies deleting session files and safe no-op on missing files.
• test_save_write_failure_resilience: Verifies handling disk write failures gracefully without raising exceptions.

Verification

• 10 tests in tests/test_history.py pass — 100% coverage on gcode/history.py.
• Full suite: 64 tests pass.
• ruff check and ruff format --check clean.

[shauryagangrade]

Merged. Thanks for your work here.

Give this repo a ⭐ so that we can reach more contributors like you :-)

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