test(BA-6921): assert the DTO rejection every request actually gets

BaseRequestModel only maps a pydantic ValidationError onto
BackendAISchemaValidationFailed inside model_validate, and every production
entry point — BodyParam, QueryParam, PathParam, headers — parses that way. The
raw ValidationError the direct constructor raises is therefore unreachable in
service, so accepting either exception let the tests pass on a rejection no
caller can observe. Reject through model_validate and assert the one error.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: jopemachine

src/ai/backend/manager/api/adapters/app_config_fragment/adapter.py

@@ -67,18 +67,20 @@ def _scope_owner(scope_type: AppConfigScopeType, scope_id: UUID | None) -> AppCo
     """Read a request's raw ``scope_id`` as the kind of owner its ``scope_type`` calls for.
 
     A request body carries ``scope_id`` as a plain UUID; only ``scope_type`` says whether it
-    names a domain or a user. The DTO validator already rejects the mismatched combinations,
-    so the final branch is a boundary guard rather than a reachable path.
+    names a domain or a user. The DTO validator already rejects both contradictions below,
+    so the raises are boundary guards rather than reachable paths.
     """
-    match scope_type, scope_id:
-        case AppConfigScopeType.PUBLIC, None:
-            return None
-        case AppConfigScopeType.DOMAIN, UUID() as owner:
-            return DomainID(owner)
-        case AppConfigScopeType.USER, UUID() as owner:
-            return UserID(owner)
-        case _:
-            raise InvalidAPIParameters(f"scope_id does not match the {scope_type.value} scope.")
+    if scope_type is AppConfigScopeType.PUBLIC:
+        if scope_id is not None:
+            raise InvalidAPIParameters("The public scope names no owner.")
+        return None
+    if scope_id is None:
+        raise InvalidAPIParameters(f"The {scope_type.value} scope needs an owner.")
+    match scope_type:
+        case AppConfigScopeType.DOMAIN:
+            return DomainID(scope_id)
+        case AppConfigScopeType.USER:
+            return UserID(scope_id)
 
 
 class AppConfigFragmentAdapter(BaseAdapter):

tests/unit/common/dto/manager/v2/app_config_fragment/test_request.py

@@ -7,7 +7,6 @@
 from typing import Any
 
 import pytest
-from pydantic import ValidationError
 
 from ai.backend.common.data.app_config.types import AppConfigScopeType
 from ai.backend.common.dto.manager.v2.app_config_fragment.request import (
@@ -72,13 +71,13 @@ def test_scope_id_matching_its_scope_type_is_accepted(
     def test_scope_id_disagreeing_with_its_scope_type_is_rejected(
         self, case: _ScopeCase, config_document: dict[str, Any]
     ) -> None:
-        with pytest.raises((BackendAISchemaValidationFailed, ValidationError)):
-            CreateAppConfigFragmentInput(
-                config_name="theme",
-                scope_type=case.scope_type,
-                scope_id=case.scope_id,
-                config=config_document,
-            )
+        with pytest.raises(BackendAISchemaValidationFailed):
+            CreateAppConfigFragmentInput.model_validate({
+                "config_name": "theme",
+                "scope_type": case.scope_type,
+                "scope_id": case.scope_id,
+                "config": config_document,
+            })
 
     @pytest.mark.parametrize(
         "scope_type",
@@ -89,9 +88,7 @@ def test_scope_id_disagreeing_with_its_scope_type_is_rejected(
     def test_scope_id_that_is_not_a_uuid_is_rejected(
         self, scope_type: AppConfigScopeType, scope_id: str, config_document: dict[str, Any]
     ) -> None:
-        # Validated from a mapping because the field is typed UUID: a string only ever
-        # reaches it from a request payload, never from a type-checked call.
-        with pytest.raises((BackendAISchemaValidationFailed, ValidationError)):
+        with pytest.raises(BackendAISchemaValidationFailed):
             CreateAppConfigFragmentInput.model_validate({
                 "config_name": "theme",
                 "scope_type": scope_type,
@@ -112,12 +109,12 @@ def test_scope_id_defaults_to_none(self, config_document: dict[str, Any]) -> Non
     def test_config_name_outside_its_length_bounds_is_rejected(
         self, config_name: str, config_document: dict[str, Any]
     ) -> None:
-        with pytest.raises((BackendAISchemaValidationFailed, ValidationError)):
-            CreateAppConfigFragmentInput(
-                config_name=config_name,
-                scope_type=AppConfigScopeType.PUBLIC,
-                config=config_document,
-            )
+        with pytest.raises(BackendAISchemaValidationFailed):
+            CreateAppConfigFragmentInput.model_validate({
+                "config_name": config_name,
+                "scope_type": AppConfigScopeType.PUBLIC,
+                "config": config_document,
+            })
 
 
 class TestUpdateAppConfigFragmentInput:
@@ -132,7 +129,7 @@ def test_config_alone_is_a_complete_body(self, config_document: dict[str, Any])
     def test_config_is_required(self) -> None:
         # Validated from a mapping rather than the constructor: a body arriving without
         # ``config`` is a runtime payload, not a call the type checker would ever allow.
-        with pytest.raises((BackendAISchemaValidationFailed, ValidationError)):
+        with pytest.raises(BackendAISchemaValidationFailed):
             UpdateAppConfigFragmentInput.model_validate({})
 
 
@@ -148,7 +145,7 @@ def test_id_and_config_are_both_required(self, config_document: dict[str, Any])
         assert item.config == config_document
 
     def test_omitting_id_is_rejected(self, config_document: dict[str, Any]) -> None:
-        with pytest.raises((BackendAISchemaValidationFailed, ValidationError)):
+        with pytest.raises(BackendAISchemaValidationFailed):
             AppConfigFragmentUpdateItem.model_validate({"config": config_document})
 
 
@@ -163,8 +160,8 @@ def test_bulk_update_accepts_items(self, config_document: dict[str, Any]) -> Non
         assert len(req.items) == 1
 
     def test_bulk_update_rejects_an_empty_batch(self) -> None:
-        with pytest.raises((BackendAISchemaValidationFailed, ValidationError)):
-            BulkUpdateAppConfigFragmentInput(items=[])
+        with pytest.raises(BackendAISchemaValidationFailed):
+            BulkUpdateAppConfigFragmentInput.model_validate({"items": []})
 
     def test_bulk_purge_accepts_ids(self) -> None:
         fragment_id = uuid.uuid4()
@@ -174,5 +171,5 @@ def test_bulk_purge_accepts_ids(self) -> None:
         assert req.ids == [fragment_id]
 
     def test_bulk_purge_rejects_an_empty_batch(self) -> None:
-        with pytest.raises((BackendAISchemaValidationFailed, ValidationError)):
-            BulkPurgeAppConfigFragmentInput(ids=[])
+        with pytest.raises(BackendAISchemaValidationFailed):
+            BulkPurgeAppConfigFragmentInput.model_validate({"ids": []})