MockTransport doesn't set the elapsed property

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?

Start by locating MockTransport and the Response elapsed property in the repository, then inspect how manually created responses are handled. Compare the three proposed behaviors and existing transport tests; done means an agreed behavior is implemented and covered by tests without requiring handler boilerplate.