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TestClient on mac takes exactly 30s for every .get call

See original GitHub issue

I previously opened this issue at FastAPI: https://github.com/tiangolo/fastapi/issues/1567, but traced the problem to Starlette.

Details

On Mac with new install of Starlette, every call to TestClient.get() takes exactly 30s to complete. The response, when it arrives, is correct.

Environment

OS: Macbook Pro 10.13.6
Starlette version: 0.13.4
Python version: 3.6

Example

Copy and paste the example from the Starlette docs https://www.starlette.io/testclient/ into a brand new venv:

from starlette.responses import HTMLResponse
from starlette.testclient import TestClient


async def app(scope, receive, send):
    assert scope['type'] == 'http'
    response = HTMLResponse('<html><body>Hello, world!</body></html>')
    await response(scope, receive, send)


def test_app():
    client = TestClient(app)
    response = client.get('/')
    assert response.status_code == 200

Alternatively, you can clone the repo at https://github.com/charlesbaynham/fastapi_mwe and use the requirements.txt to duplicate my environment. Running python test_starlette.py takes 30s. This repo also contains a cProfile of the test which looks like this:

Issue Analytics

State:
Created 3 years ago
Comments:7 (3 by maintainers)

Top GitHub Comments

15reactions

mcmxcommented, Nov 5, 2020

In my case, each test takes around 7.5 seconds to run, by @erewok comment, I took a look at TestClient which defines base_url as ‘http://testserver’ by default, which is not resolvable of course.

So I changed the call to TestClient for this:

client = TestClient(app, base_url='http://localhost')

Now the test runs in 0.3s, this is running MacOS 10.14.6 in a MacBook Pro, Python 3.8.0.

Hope this helps some else.

1reaction

charlesbaynhamcommented, Jun 22, 2020

After some digging I tracked it down to the Search Domains setting of my local network, this was set to “local”, removing that immediately fixed the issue.

That sounds familiar, I’ve been messing around with OpenWRT recently. Thanks for your help and sorry to have wasted your time!