diff --git a/api/tests/unit_tests/services/test_conversation_service.py b/api/tests/unit_tests/services/test_conversation_service.py
index 641731c4384..3d73922fd4e 100644
--- a/api/tests/unit_tests/services/test_conversation_service.py
+++ b/api/tests/unit_tests/services/test_conversation_service.py
@@ -8,7 +8,7 @@ in-memory SQLite sessions with persisted ORM rows.
 """
 
 import json
-from unittest.mock import MagicMock, Mock, patch
+from unittest.mock import MagicMock, patch
 
 import pytest
 from sqlalchemy import asc, desc, event
@@ -17,6 +17,11 @@ from sqlalchemy.orm import Session
 from core.app.entities.app_invoke_entities import InvokeFrom
 from libs.datetime_utils import naive_utc_now
 from models import Account, ConversationVariable
+from models.agent import (
+    AgentConfigVersionKind,
+    AgentWorkingResourceStatus,
+    AgentWorkspaceBinding,
+)
 from models.enums import AppStatus, ConversationFromSource, ConversationStatus
 from models.model import App, AppMode, Conversation
 from services import conversation_service
@@ -58,6 +63,21 @@ def _conversation_variable(
     )
 
 
+def _workspace_binding(binding_id: str) -> AgentWorkspaceBinding:
+    return AgentWorkspaceBinding(
+        id=binding_id,
+        tenant_id=TENANT_ID,
+        app_id=APP_ID,
+        workspace_id="workspace-1",
+        agent_id="agent-1",
+        base_home_snapshot_id=None,
+        agent_config_version_id="config-1",
+        agent_config_version_kind=AgentConfigVersionKind.SNAPSHOT,
+        backend_binding_ref="backend-binding-1",
+        status=AgentWorkingResourceStatus.ACTIVE,
+    )
+
+
 class ConversationServiceTestDataFactory:
     """
     Factory for creating test ORM objects.
@@ -157,7 +177,7 @@ def test_delete_retires_then_commits_before_enqueue(monkeypatch: pytest.MonkeyPa
     sqlite_session.add(conversation)
     sqlite_session.flush()
     events: list[str] = []
-    get_binding = MagicMock(return_value=Mock(id="conversation-binding-1"))
+    get_binding = MagicMock(return_value=_workspace_binding("conversation-binding-1"))
     retire_binding = MagicMock(side_effect=lambda **_kwargs: events.append("retire") or "conversation-binding-1")
     monkeypatch.setattr(ConversationService, "get_conversation", MagicMock(return_value=conversation))
     monkeypatch.setattr(AgentWorkspaceService, "get_active_binding", get_binding)
@@ -185,12 +205,16 @@ def test_delete_commit_failure_does_not_enqueue(monkeypatch: pytest.MonkeyPatch,
     sqlite_session.flush()
     rollback_events: list[str] = []
     event.listen(sqlite_session, "after_rollback", lambda _session: rollback_events.append("rollback"))
-    monkeypatch.setattr(sqlite_session, "commit", MagicMock(side_effect=RuntimeError("commit failed")))
+
+    def fail_commit(_session: Session) -> None:
+        raise RuntimeError("commit failed")
+
+    event.listen(sqlite_session, "before_commit", fail_commit, once=True)
     monkeypatch.setattr(ConversationService, "get_conversation", MagicMock(return_value=conversation))
     monkeypatch.setattr(
         AgentWorkspaceService,
         "get_active_binding",
-        MagicMock(return_value=Mock(id="binding-1")),
+        MagicMock(return_value=_workspace_binding("binding-1")),
     )
     monkeypatch.setattr(AgentWorkspaceService, "retire_binding", MagicMock(return_value="binding-1"))
     enqueue_collection = MagicMock()