fix(proxies): skip a proxy provider that fails to load

A bare --proxy query moves past it; naming it (--proxy nordvpn:us) fails with the load error. dl, search and the REST path share one loader.

tests/core/test_proxy_loading.py

@@ -0,0 +1,63 @@
+"""Unit tests for the shared proxy provider loader: a proxy provider that fails to load is skipped
+by a bare query and reported by a query that names it."""
+
+from __future__ import annotations
+
+import logging
+
+import pytest
+import requests
+
+from unshackle.core.config import config
+from unshackle.core.proxies import NordVPN, SurfsharkVPN
+from unshackle.core.proxies.resolve import Unavailable, find_provider, load_proxy_providers, resolve_proxy
+
+pytestmark = pytest.mark.unit
+
+CREDENTIALS = {"username": "a" * 24, "password": "b" * 24}
+OTHERS = ("basic", "expressvpn", "protonvpn", "windscribevpn", "gluetun", "hola", "controld")
+
+
+@pytest.fixture(autouse=True)
+def nordvpn_down_surfshark_up(monkeypatch: pytest.MonkeyPatch) -> None:
+    def refuse() -> list[dict]:
+        raise requests.ConnectionError("no route to api.nordvpn.com")
+
+    clusters = [{"countryCode": "US", "connectionName": "us-dal.prod.surfshark.com", "location": "Dallas"}]
+    monkeypatch.setattr(config, "proxy_providers", {"nordvpn": CREDENTIALS, "surfsharkvpn": CREDENTIALS})
+    monkeypatch.setattr(NordVPN, "get_countries", staticmethod(refuse))
+    monkeypatch.setattr(SurfsharkVPN, "get_countries", staticmethod(lambda: clusters))
+
+
+def test_failed_provider_is_kept_as_unavailable(caplog: pytest.LogCaptureFixture) -> None:
+    with caplog.at_level(logging.WARNING):
+        nordvpn, surfshark = load_proxy_providers(OTHERS)
+    assert isinstance(nordvpn, Unavailable) and nordvpn.name == "NordVPN"
+    assert isinstance(surfshark, SurfsharkVPN)
+    assert "NordVPN proxy provider could not load" in caplog.text
+
+
+def test_bare_query_skips_the_failed_provider() -> None:
+    uri = resolve_proxy("us", load_proxy_providers(OTHERS))
+    assert uri.endswith("@us-dal.prod.surfshark.com:443")
+
+
+def test_query_naming_another_provider_still_works() -> None:
+    uri = resolve_proxy("surfsharkvpn:us", load_proxy_providers(OTHERS))
+    assert uri.endswith("@us-dal.prod.surfshark.com:443")
+
+
+@pytest.mark.parametrize("name", ["nordvpn", "NordVPN"])
+def test_query_naming_the_failed_provider_reports_why(name: str) -> None:
+    with pytest.raises(ValueError, match="NordVPN could not load: no route to api.nordvpn.com"):
+        resolve_proxy(f"{name}:us", load_proxy_providers(OTHERS))
+
+
+def test_query_naming_an_unknown_provider_lists_the_loaded_ones() -> None:
+    with pytest.raises(ValueError, match=r"'mullvad' was not found. Available: \['SurfsharkVPN'\]"):
+        find_provider(load_proxy_providers(OTHERS), "mullvad")
+
+
+def test_raise_errors_raises_the_load_failure() -> None:
+    with pytest.raises(requests.ConnectionError):
+        load_proxy_providers(OTHERS, raise_errors=True)