ImportError: ImportError: cannot import name 'BaseSettings' from 'pydantic'

Root cause

The project is running with Pydantic v2, where BaseSettings was removed from the pydantic package and moved into the separate pydantic-settings distribution. app/config.py still uses the Pydantic v1 import path `from pydantic import BaseSettings`.

Minimal fix

Add the pydantic-settings package to the project dependencies and update the settings import in app/config.py to `from pydantic_settings import BaseSettings` while keeping other Pydantic imports, such as Field, imported from `pydantic`. Then rerun `pytest tests/test_config.py -q`.