Add tests/tools/test_computer_use_vision_routing.py — 28 unit tests
that pin the contract of the new vision-routing helper introduced in
the previous commit:
* TestExplicitAuxVisionOverride (12 cases): mirror the
auxiliary.vision detection rules used by agent.image_routing so
the capture path and the user-attached-image path agree on what
counts as an explicit override (provider/model/base_url with
non-blank, non-'auto' values).
* TestRouteDecision (7 cases): pin the policy itself — explicit
override always wins, vision-capable + native-tool-result keeps
multimodal, everything else fails closed and routes to aux.
* TestLookupHelpers (5 cases): defensive paths for the models.dev /
tool-result-support lookups (blank inputs, exceptions, missing
caps).
* TestModuleSurface (4 cases): pin the public/__all__ surface and
keep internal helpers addressable so the integration test in the
next commit can monkeypatch them deterministically.
Run with:
scripts/run_tests.sh tests/tools/test_computer_use_vision_routing.py
