Add template and generated artifact contracts

tests/test_template_contract.py

@@ -0,0 +1,76 @@
+from __future__ import annotations
+
+import unittest
+
+from govoplan_core.core.files import (
+    CAPABILITY_FILES_ARTIFACT_STORE,
+    ManagedArtifactRef,
+    ManagedArtifactStore,
+    ManagedArtifactWriteRequest,
+)
+from govoplan_core.core.templates import (
+    CAPABILITY_TEMPLATE_CATALOG,
+    CAPABILITY_TEMPLATE_RENDERER,
+    TemplateCatalogProvider,
+    TemplateRenderRequest,
+    TemplateRendererProvider,
+)
+
+
+class _Catalog:
+    def list_templates(self, session, principal, **kwargs):
+        del session, principal, kwargs
+        return ()
+
+    def get_template(self, session, principal, **kwargs):
+        del session, principal, kwargs
+        return None
+
+    def check_compatibility(self, session, principal, **kwargs):
+        del session, principal, kwargs
+        return None
+
+
+class _Renderer:
+    def render(self, session, principal, *, request):
+        del session, principal, request
+        return None
+
+
+class _Store:
+    def store_artifact(self, session, principal, *, request):
+        del session, principal
+        return ManagedArtifactRef(
+            file_asset_id="file-1",
+            file_version_id="version-1",
+            filename=request.filename,
+            display_path=request.filename,
+            content_type=request.content_type,
+            size_bytes=len(request.payload),
+            sha256="0" * 64,
+        )
+
+
+class TemplateContractTests(unittest.TestCase):
+    def test_capability_names_and_runtime_protocols_are_stable(self) -> None:
+        self.assertEqual("templates.catalog", CAPABILITY_TEMPLATE_CATALOG)
+        self.assertEqual("templates.renderer", CAPABILITY_TEMPLATE_RENDERER)
+        self.assertEqual("files.artifact_store", CAPABILITY_FILES_ARTIFACT_STORE)
+        self.assertIsInstance(_Catalog(), TemplateCatalogProvider)
+        self.assertIsInstance(_Renderer(), TemplateRendererProvider)
+        self.assertIsInstance(_Store(), ManagedArtifactStore)
+
+    def test_requests_do_not_expose_consumer_or_files_models(self) -> None:
+        render = TemplateRenderRequest(template_id="template-1")
+        artifact = ManagedArtifactWriteRequest(
+            filename="result.html",
+            payload=b"result",
+            content_type="text/html",
+        )
+        self.assertEqual((), render.items)
+        self.assertEqual("preview", render.mode)
+        self.assertEqual("Generated", artifact.folder)
+
+
+if __name__ == "__main__":
+    unittest.main()