MockTransport doesn't set the elapsed property

[Kludex]

Originally opened by @ionelmc on 2025-11-24 20:54:00 in encode/httpx

This is not a nice solution:

def handler(request):
    resp = httpx.Response(200, json={"text": "Hello, world!"})
    resp.elapsed = timedelta(.......
    return resp

If you have dispatch code in that handler that can easily get boilerplatey.

I think httpx should do either of these:

• MockTransport take the duration as an optional argument
• httpx provide a decorator, so you can wrap your handler in it
• automatically set a duration of 0 for manually created Response objects - why error out if the data is already there?

[Kludex]

Originally posted by @karpetrosyan on 2025-12-10T14:21:41Z

This issue already has two PRs with proposed fixes, but for now I suggest a very simple way to fix it without extra boilerplate code. We can close the PRs until we make a good design decision around this.

You can write a very simple wrapper around that mock transport and use it instead of the default one. Then you can handle the elapsed time for mocked responses however you want, like this.

from __future__ import annotations

from datetime import timedelta

import httpx


class CustomMock(httpx.BaseTransport):
    def __init__(self, next_transport: httpx.BaseTransport | None = None) -> None:
        self._next_transport = httpx.MockTransport() if next_transport is None else next_transport

    def handle_request(self, request: httpx.Request) -> httpx.Response:
        response = self._next_transport.handle_request(request)
        response.elapsed = timedelta()
        return response

# use custom mock instead of the default mock