Does not work examples on page 'Testing'

[manlix]

Issue description:

Got error running code examples from chapter Testing:

• Sub-chapter Testing file
• Sub-chapter Testing: extended example

Expected result:

Code works properly.

Actual result:

Code does not work.

For sub-chapter Testing file got error:

    from .main import app
E   ImportError: attempted relative import with no known parent package

For sub-chapter Testing: extended example got error:

    from .main_b import app
E   ImportError: attempted relative import with no known parent package

Preconditions:

• Python: 3.9.5
• FastAPI: 0.65.2
• pytest: 6.2.4

How to reproduce (1st example):

Run examples code from sub-chapter Testing file

Create main.py:

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_main():
    return {"msg": "Hello World"}

Create test_main.py:

from fastapi.testclient import TestClient

from .main import app

client = TestClient(app)


def test_read_main():
    response = client.get("/")
    assert response.status_code == 200
    assert response.json() == {"msg": "Hello World"}

After that run pytest:

$ pytest

Got error:

    from .main import app
E   ImportError: attempted relative import with no known parent package

How to reproduce (2nd example):

Run example code from sub-chapter Testing: extended example

Create main_b.py

from typing import Optional

from fastapi import FastAPI, Header, HTTPException
from pydantic import BaseModel

fake_secret_token = "coneofsilence"

fake_db = {
    "foo": {"id": "foo", "title": "Foo", "description": "There goes my hero"},
    "bar": {"id": "bar", "title": "Bar", "description": "The bartenders"},
}

app = FastAPI()


class Item(BaseModel):
    id: str
    title: str
    description: Optional[str] = None


@app.get("/items/{item_id}", response_model=Item)
async def read_main(item_id: str, x_token: str = Header(...)):
    if x_token != fake_secret_token:
        raise HTTPException(status_code=400, detail="Invalid X-Token header")
    if item_id not in fake_db:
        raise HTTPException(status_code=404, detail="Item not found")
    return fake_db[item_id]


@app.post("/items/", response_model=Item)
async def create_item(item: Item, x_token: str = Header(...)):
    if x_token != fake_secret_token:
        raise HTTPException(status_code=400, detail="Invalid X-Token header")
    if item.id in fake_db:
        raise HTTPException(status_code=400, detail="Item already exists")
    fake_db[item.id] = item
    return item

Create test_main_b.py:

from fastapi.testclient import TestClient

from .main_b import app

client = TestClient(app)


def test_read_item():
    response = client.get("/items/foo", headers={"X-Token": "coneofsilence"})
    assert response.status_code == 200
    assert response.json() == {
        "id": "foo",
        "title": "Foo",
        "description": "There goes my hero",
    }


def test_read_item_bad_token():
    response = client.get("/items/foo", headers={"X-Token": "hailhydra"})
    assert response.status_code == 400
    assert response.json() == {"detail": "Invalid X-Token header"}


def test_read_inexistent_item():
    response = client.get("/items/baz", headers={"X-Token": "coneofsilence"})
    assert response.status_code == 404
    assert response.json() == {"detail": "Item not found"}


def test_create_item():
    response = client.post(
        "/items/",
        headers={"X-Token": "coneofsilence"},
        json={"id": "foobar", "title": "Foo Bar", "description": "The Foo Barters"},
    )
    assert response.status_code == 200
    assert response.json() == {
        "id": "foobar",
        "title": "Foo Bar",
        "description": "The Foo Barters",
    }


def test_create_item_bad_token():
    response = client.post(
        "/items/",
        headers={"X-Token": "hailhydra"},
        json={"id": "bazz", "title": "Bazz", "description": "Drop the bazz"},
    )
    assert response.status_code == 400
    assert response.json() == {"detail": "Invalid X-Token header"}


def test_create_existing_item():
    response = client.post(
        "/items/",
        headers={"X-Token": "coneofsilence"},
        json={
            "id": "foo",
            "title": "The Foo ID Stealers",
            "description": "There goes my stealer",
        },
    )
    assert response.status_code == 400
    assert response.json() == {"detail": "Item already exists"}

After that run pytest:

$ pytest

Got error:

    from .main_b import app
E   ImportError: attempted relative import with no known parent package

The cause of the problem:

Created code is not a part of package — there isn't __init__.py inside current directory.

Solution:

There is small fix in PR #3380 for docs.

[tiangolo]

Thanks for the report! Indeed, running the examples as is wouldn't work.

I just updated the docs to include a Python package with a __init__.py file, so that running the example would work, and the tests can keep working.

If that solves it for you, please remember to close the issue. 🍰

[github-actions]

Assuming the original need was handled, this will be automatically closed now. But feel free to add more comments or create new issues or PRs.

[ENGRZULQARNAIN]

we are facing the following issue :
from .routers import users
ImportError: attempted relative import with no known parent package

files structure :
.
├── app
│   ├── init.py
│   ├── main.py
│   └── routers
│   │ ├── init.py
│   │ ├── blogs.py
│   │ └── users.py
│   └── internal
│   ├── init.py
│   └── admin.py