Suppose my main.py
is like this (this is a simplified example, in my app I use an actual database and I have two different database URIs for development and testing):
from fastapi import FastAPI
from pydantic import BaseSettings
app = FastAPI()
class Settings(BaseSettings):
ENVIRONMENT: str
class Config:
env_file = ".env"
case_sensitive = True
settings = Settings()
databases = {
"dev": "Development",
"test": "Testing"
}
database = databases[settings.ENVIRONMENT]
@app.get("/")
def read_root():
return {"Environment": database}
while the .env
is
ENVIRONMENT=dev
Suppose I want to test my code and I want to set ENVIRONMENT=test
to use a testing database. What should I do? In FastAPI documentation (https://fastapi.tiangolo.com/advanced/settings/#settings-and-testing) there is a good example but it is about dependencies, so it is a different case as far as I know.
My idea was the following (test.py
):
import pytest
from fastapi.testclient import TestClient
from main import app
@pytest.fixture(scope="session", autouse=True)
def test_config(monkeypatch):
monkeypatch.setenv("ENVIRONMENT", "test")
@pytest.fixture(scope="session")
def client():
return TestClient(app)
def test_root(client):
response = client.get("/")
assert response.status_code == 200
assert response.json() == {"Environment": "Testing"}
but it doesn't work.
Furthermore I get this error:
ScopeMismatch: You tried to access the 'function' scoped fixture 'monkeypatch' with a 'session' scoped request object, involved factories
test.py:7: def test_config(monkeypatch)
env\lib\site-packages\_pytest\monkeypatch.py:16: def monkeypatch()
while from pytest
official documentation it should work (https://docs.pytest.org/en/3.0.1/monkeypatch.html#example-setting-an-environment-variable-for-the-test-session). I have the latest version of pytest
installed.
I tried to use specific test environment variables because of this: https://pydantic-docs.helpmanual.io/usage/settings/#field-value-priority.
To be honest I'm lost, my only real aim is to have a different test configuration (in the same way Flask works: https://flask.palletsprojects.com/en/1.1.x/tutorial/tests/#setup-and-fixtures). Am I approaching the problem the wrong way?
PydanticSettings
are mutable, so you can simply override them in your test.py
:
from main import settings
settings.ENVIRONMENT = 'test'