Add respx

respx is an HTTP request mocking library for httpx, providing the
same role for async HTTP testing that requests-mock provides for
synchronous requests-based code. It enables declarative HTTP stubbing
in pytest for projects using httpx.AsyncClient.

* Is the library actively maintained?
  Yes. 48 releases over 6 years (2019-2026). Author Jonas Lundberg
  (lundberg). Latest release 0.23.1 (April 2026). Active issue
  tracker and regular PRs merged.

* Is the library good code?
  Yes. Fully typed, pytest plugin integration, CI tests Python
  3.8-3.14. Single runtime dependency (httpx>=0.25.0).

* Is the library license compatible?
  Yes, BSD licensed.

* Is the library already packaged in the distros we target?
  Debian (trixie stable): python3-respx 0.22.0-3

* Is the function of this library already covered by other libraries
  in global-requirements.txt?
  No. requests-mock covers synchronous requests testing. No httpx
  mocking library exists in global-requirements. respx is the
  standard httpx mock (recommended by the httpx documentation itself)
  and fills this gap for projects adopting async HTTP via httpx.

* Is the library required for an OpenStack project? Which?
  Yes, keystoneauth1 AsyncSession tests (feature/async-session
  branch) which use httpx.AsyncClient for async HTTP calls.

* If the library release is managed by the OpenStack release process?
  No, it is not managed by OpenStack.

Needed-By: https://review.opendev.org/c/openstack/keystoneauth/+/995233
Generated-By: claude-opus-4-6 (OpenCode)
Change-Id: Ic46054d32514bc4b95e6457c5ffacdbbd859b0e0
Signed-off-by: Adam Harwell <flux.adam@gmail.com>

global-requirements.txt

@@ -259,6 +259,7 @@ python-subunit  # Apache-2.0/BSD
 pyzmq  # LGPL+BSD
 redis!=4.0.0  # MIT
 requests-mock  # Apache-2.0
+respx  # BSD-3-Clause
 retrying!=1.3.0  # Apache-2.0
 sadisplay  # BSD
 selenium  # Apache-2.0

upper-constraints.txt

@@ -578,3 +578,4 @@ actdiag===3.0.0
 sphinxcontrib-applehelp===2.0.0
 scikit-learn===1.9.0
 a2wsgi===1.10.10
+respx===0.23.1