feat: complete langchain test script

[codomposer]

Add LangChain Integration Tests

Summary

Added essential test coverage for the Chainlit LangChain integration.

Changes

• Added 18 tests across 3 test files
• Tests cover core LangChain callback functionality
• All tests passing ✅

Test Files Added

• backend/tests/langchain/__init__.py - Package initialization
• backend/tests/langchain/test_async_callback.py - 6 async callback tests
• backend/tests/langchain/test_sync_callback.py - 8 helper class tests
• backend/tests/langchain/test_chain_types.py - 4 chain type tests
• backend/tests/langchain/README.md - Test documentation

Test Coverage

• ✅ Tracer initialization and configuration
• ✅ LLM callbacks (start, token streaming)
• ✅ Step creation and management
• ✅ Error handling
• ✅ Helper classes (FinalStreamHelper, GenerationHelper)
• ✅ Run filtering and parent ID management
• ✅ Chain types and nested hierarchies

Running Tests

pytest tests/langchain/ -v

Dependencies

All dependencies already in pyproject.toml:

• langchain>=0.2.4,<0.3.0
• pytest>=8.3.2
• pytest-asyncio>=0.23.8

Notes

• No source code changes required
• Compatible with langchain 0.2.x
• Uses existing test fixtures from tests/conftest.py

Contribution by Gittensor, learn more at https://gittensor.io/

[cubic-dev-ai]

No issues found across 5 files

[hayescode]

@codomposer can you remove the readme?

[codomposer]

@hayescode Done, I've removed