test_pydantic.py

import os
from pydantic_settings import BaseSettings
from typing import List, Union
from pydantic import field_validator

class Settings(BaseSettings):
    ALLOWED_ORIGINS: Union[str, List[str]] = ["http://localhost:3000"]

    @field_validator("ALLOWED_ORIGINS", mode="before")
    @classmethod
    def assemble_cors_origins(cls, v):
        if isinstance(v, str) and not v.startswith("["):
            return [i.strip() for i in v.split(",") if i.strip()]
        return v

os.environ["ALLOWED_ORIGINS"] = "http://localhost:3000,http://localhost:8080"
print(Settings().ALLOWED_ORIGINS)