I'm having a circular problem that I'm not able to solve. I started my project as follows:

.
├── conf
│   ├── __init__.py
│   └── server.py
├── __init__.py
├── main.py
├── requirements.txt
└── tests
    ├── __init__.py
    └── v1
        ├── __init__.py
        └── test_item.py

In main.py I have:

from fastapi import FastAPI
import uvicorn

from conf.server import HOST, PORT

app = FastAPI()


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

if __name__ == '__main__':
    uvicorn.run("main:app", host=HOST, port=PORT, reload=True)

In 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() == {"message": "Hello World"}

The error I get when I run the script from the same level as main.py with pytest:

C:\Python39\lib\importlib\__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests\v1\test_item.py:3: in <module>
    from main import app
E   ModuleNotFoundError: No module named 'main'

If I write the name of the folder before main:

from api.main import app

I get an error with the con/server.py module:

Hint: make sure your test modules/packages have valid Python names.
Traceback:
C:\Python39\lib\importlib\__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests\v1\test_item.py:3: in <module>
    from api.main import app
main.py:4: in <module>
    from conf.server import HOST, PORT
E   ModuleNotFoundError: No module named 'conf'

If I now change in main to include the name of the folder:

from api.conf.server import HOST, PORT

The test finally works, but now If I try to run the server wiht python main.py it will not work anymore:

    from api.conf.server import HOST, PORT
ModuleNotFoundError: No module named 'api'

What I'm doing wrong to get into this loop?