fix(import): add decrypts_samples to ImportService

tests/core/test_import_service_contract.py

@@ -0,0 +1,19 @@
+"""ImportService and RemoteService stand in for a Service in dl, so they have every method dl calls on one."""
+
+from __future__ import annotations
+
+import re
+from pathlib import Path
+
+import pytest
+
+from unshackle.commands import dl as dl_module
+from unshackle.core.import_service import ImportService
+from unshackle.core.remote_service import RemoteService
+
+
+@pytest.mark.parametrize("cls", [ImportService, RemoteService])
+def test_stand_in_service_has_every_method_dl_calls(cls: type) -> None:
+    called = set(re.findall(r"\bservice\.(\w+)\(", Path(dl_module.__file__).read_text(encoding="utf-8")))
+    assert called
+    assert sorted(name for name in called if not hasattr(cls, name)) == []

unshackle/core/import_service.py

@@ -765,6 +765,12 @@ class ImportService:
             "license through a CDM: export the title again with the tracks you need selected."
         )
 
+    def decrypts_samples(self, track: AnyTrack) -> bool:
+        return False
+
+    def get_sample_decrypter(self, track: AnyTrack, entry: int) -> bytes:
+        raise NotImplementedError("An import does not decrypt samples")
+
     def on_segment_downloaded(self, track: AnyTrack, segment: Any) -> None:
         pass