Prevent Pytest from reusing app object between different test files

I have a project with multiple route files, each of which has an APIRouter. I include all routers in my main.py as follows:

from init import app  import customer  import receipt    app.include_router(customer.router, prefix='/api/customer', tags=["Customer"])  app.include_router(receipt.router, prefix='/api/receipt', tags=["Receipt"])  

init.py:

from fastapi import FastAPI  app = FastAPI()  

In customer.py I have this (simplified) code:

from fastapi import APIRouter  from pydantic import BaseModel    router = APIRouter()    class CustomerModel(BaseModel):      name: str    @router.post('/')  def register_new_customer(data: CustomerModel):      pass  

in my receipt.py I have similar code:

from fastapi import APIRouter  from pydantic import BaseModel    router = APIRouter()    class ReceiptModel(BaseModel):      price: float    @router.post('/')  def add_new_receipt(data: ReceiptModel):      pass  

I also have unit tests for both files. test_receipt.py:

from receipt import router  from init import app    app.include_router(router)  client = TestClient(app)    class TestReceiptsRoutes:      def test_can_create_new_receipt(self):          response = client.post('/', json={'price': 10.0})          assert response.status_code == 200  

and similar for test_customer.py

If i run each file individually, e.g. pytest test_receipt.py or pytest test_customer.py it works fine, but when i run them together, my test_receipt.py fails, saying response.status_code is 422. What happens is that my app adds both POST routes on / path, so when receipt runs the test, it's actually making a call to the customer route and fails validation.

Question: how can I ensure that app is not reused between test files?

I know I can just copy/paste the app.include_router lines from main into the tests (with full paths), and that's what I'm currently doing as a workaround, I was just wondering if there's a way to ensure that app is isolated b/w each test suite.

https://stackoverflow.com/questions/65930017/prevent-pytest-from-reusing-app-object-between-different-test-files January 28, 2021 at 10:02AM