test(remote): add RemoteService method-contract tests

tests/remote/unit/test_remote_service_contract.py

@@ -0,0 +1,47 @@
+"""Contract tests for the RemoteService adapter.
+
+RemoteService copies the Service interface but does not inherit from it. When a
+method is added to the base Service and wired into dl.py, nothing forces it onto
+the adapter, so it can go missing here until a real download calls it. These
+tests pin the methods dl.py depends on so a gap fails in CI, not on the devbox.
+"""
+
+from __future__ import annotations
+
+import pytest
+
+from unshackle.core.remote_service import RemoteService
+
+pytestmark = pytest.mark.unit
+
+SERVICE_CONTRACT = (
+    "authenticate",
+    "get_titles",
+    "get_titles_cached",
+    "get_tracks",
+    "get_chapters",
+    "get_widevine_license",
+    "get_playready_license",
+    "get_clearkey_license",
+    "get_widevine_service_certificate",
+    "resolve_server_keys",
+    "on_segment_downloaded",
+    "on_track_downloaded",
+    "on_track_decrypted",
+    "on_track_repacked",
+    "on_track_multiplex",
+    "close",
+)
+
+
+@pytest.mark.parametrize("name", SERVICE_CONTRACT)
+def test_remote_service_implements_contract(name: str) -> None:
+    assert callable(getattr(RemoteService, name, None)), f"RemoteService is missing {name}()"
+
+
+def test_get_clearkey_license_returns_none() -> None:
+    # Regression: clearkey uses no CDM, so the adapter returns None and the
+    # framework POSTs the manifest Laurl itself. __new__ skips the networked
+    # __init__, so the method must not touch self.
+    svc = RemoteService.__new__(RemoteService)
+    assert svc.get_clearkey_license(challenge=b"", title=None, track=None) is None