Add test suite for the Bonsai Viewer Autodesk connector

Introduce pytest coverage for the previously untested connector — rpc,
cache, settings, autodesk (auth + APS client) and connector handlers —
94 tests, runnable via the new `test` optional-dependency extra.

To make HTTP, time and the OAuth redirect testable without a network or
real sockets, add dependency-injection seams to autodesk.py:
AuthSessionService and ApsClient accept an optional httpx transport;
AuthSessionService accepts an injectable clock and callback_waiter; and
_wait_for_callback is extracted to the module-level wait_for_oauth_callback.
All seams default to the previous behaviour.

Remove the APS_CLIENT_ID environment-variable override: the client id now
comes solely from settings.json, collapsing settings.load_client_id and
simplifying the settings dialog.

CI: the build-bonsaiviewer-autodesk workflow gains a `test` job
(Python 3.11 + 3.13) that gates the build matrix.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/bonsaiviewer-autodesk/tests/conftest.py

@@ -0,0 +1,72 @@
+"""Shared fixtures for the bonsaiviewer-autodesk test suite."""
+
+from __future__ import annotations
+
+import keyring
+import keyring.backend
+import keyring.errors
+import pytest
+
+from bonsaiviewer_autodesk import cache as cache_module
+from bonsaiviewer_autodesk import settings as settings_module
+
+
+@pytest.fixture
+def cache_dir(tmp_path, monkeypatch):
+    """Redirect ``bonsaiviewer_autodesk.cache`` at an isolated tmp directory.
+
+    Patches ``cache_root`` itself rather than ``XDG_CACHE_HOME`` so the
+    redirect holds on every platform — on macOS/Windows ``cache_root`` ignores
+    the XDG variables. Returns the directory ``cache_root()`` now resolves to.
+    """
+    root = tmp_path / "cache" / "bonsaiviewer-autodesk"
+    root.mkdir(parents=True, exist_ok=True)
+    monkeypatch.setattr(cache_module, "cache_root", lambda: root)
+    return root
+
+
+@pytest.fixture
+def config_dir(tmp_path, monkeypatch):
+    """Redirect ``bonsaiviewer_autodesk.settings`` at an isolated tmp directory.
+
+    Patches ``config_root`` directly (platform-independent). Returns the
+    directory ``config_root()`` now resolves to.
+    """
+    root = tmp_path / "config" / "bonsaiviewer-autodesk"
+    root.mkdir(parents=True, exist_ok=True)
+    monkeypatch.setattr(settings_module, "config_root", lambda: root)
+    return root
+
+
+class InMemoryKeyring(keyring.backend.KeyringBackend):
+    """A keyring backend that keeps secrets in a dict — never touches the OS."""
+
+    priority = 1  # type: ignore[assignment]
+
+    def __init__(self) -> None:
+        super().__init__()
+        self._store: dict[tuple[str, str], str] = {}
+
+    def get_password(self, service: str, username: str) -> str | None:
+        return self._store.get((service, username))
+
+    def set_password(self, service: str, username: str, password: str) -> None:
+        self._store[(service, username)] = password
+
+    def delete_password(self, service: str, username: str) -> None:
+        try:
+            del self._store[(service, username)]
+        except KeyError as exc:
+            raise keyring.errors.PasswordDeleteError("not found") from exc
+
+
+@pytest.fixture
+def memory_keyring():
+    """Swap in the in-memory keyring backend for the duration of a test."""
+    backend = InMemoryKeyring()
+    previous = keyring.get_keyring()
+    keyring.set_keyring(backend)
+    try:
+        yield backend
+    finally:
+        keyring.set_keyring(previous)