test: Unit Tests for Vectorisers

[frayle-ons]

resolves #215

✨ Summary

This PR adds a test folders, containing a general readme about testing and concrete implementations for a subgroup of unit tests for the Vectoriser classes. All 4 of the Vectorisers (base, gcp, huggingface, and ollama) have their own unit test file. There is a corresponding readme for the test_vectorisers folder which details the different features of each unit tested vectoriser.The readme files are taken from an earlier branch #217 which was used to write an early stage plan for unit testing.

📜 Changes Introduced

• (test:) added folder for tests and readmes for tests in general and for specific vectorisers subfolder
• (test:) added gcp, huggingface, ollama and base vectoriser unit test files to test functionality.

✅ Checklist

Implemented code passes all pre-commit checks.

🔍 How to Test

Navigating to the route directory of the project, and using uv astral, the user can trigger Pytest to execute the testing with:

uv run pytest

For each of the vectoriser tests it is necessary to have the cooresponding optional dependencies installed. To install all of these before running the above, the user can perform a sync operation:

uv sync --extra huggingface --extra gcp --extra ollama

If you want to run a single test file this is also possible by specifying the path. (with the optional flag for verbose logging):

uv run pytest tests/test_vectorisers/test_ollama_vectoriser.py -v

this will trigger just the tests for the Ollama vectoriser.