test(proxy): cover resilient extension loading

headroom/proxy/extensions.py

@@ -138,8 +138,6 @@ def install_all(
             # A failing extension disables *itself* and the proxy keeps running
             # without it — covers environment/auth failures and compatibility
             # errors (e.g. a plugin built against a core API this version lacks).
-            # ponytail: if an extension ever needs mandatory fail-closed abort,
-            # define ExtensionFatalError in this module and re-raise it here.
             log.warning(
                 "proxy extension %r failed to install and was skipped: %s",
                 name,

tests/test_proxy_extensions.py

@@ -0,0 +1,46 @@
+from __future__ import annotations
+
+import logging
+from typing import Any
+
+from headroom.proxy import extensions
+
+
+def test_install_all_skips_failed_extension_and_continues(
+    caplog,
+    capsys,
+    monkeypatch,
+) -> None:
+    calls: list[str] = []
+
+    def good(app: Any, config: Any) -> None:
+        calls.append("good")
+
+    def bad(app: Any, config: Any) -> None:
+        calls.append("bad")
+        raise RuntimeError("missing optional dependency")
+
+    monkeypatch.setattr(
+        extensions,
+        "discover",
+        lambda: iter([("bad_ext", bad), ("good_ext", good)]),
+    )
+
+    with caplog.at_level(logging.WARNING, logger=extensions.log.name):
+        installed = extensions.install_all(object(), object(), enabled=["bad_ext", "good_ext"])
+
+    assert installed == ["good_ext"]
+    assert calls == ["bad", "good"]
+    assert "bad_ext" in capsys.readouterr().err
+    assert "failed to install and was skipped" in caplog.text
+    assert "proxy extensions skipped due to install errors: bad_ext" in caplog.text
+
+
+def test_install_all_warns_for_missing_requested_extension(caplog, monkeypatch) -> None:
+    monkeypatch.setattr(extensions, "discover", lambda: iter([]))
+
+    with caplog.at_level(logging.WARNING, logger=extensions.log.name):
+        installed = extensions.install_all(object(), object(), enabled=["missing_ext"])
+
+    assert installed == []
+    assert "proxy extensions requested but not found: missing_ext" in caplog.text