feat: expose credential service in readonly context

tests/unittests/agents/test_readonly_context.py

@@ -2,15 +2,25 @@ from types import MappingProxyType
 from unittest.mock import MagicMock
 
 from google.adk.agents.readonly_context import ReadonlyContext
+from google.adk.auth.credential_service.base_credential_service import BaseCredentialService
 import pytest
 
 
+class DummyCredentialService(BaseCredentialService):
+  async def load_credential(self,auth_config, tool_context):
+    pass
+
+  async def save_credential(self,auth_config, tool_context):
+    pass
+
+
 @pytest.fixture
 def mock_invocation_context():
   mock_context = MagicMock()
   mock_context.invocation_id = "test-invocation-id"
   mock_context.agent.name = "test-agent-name"
   mock_context.session.state = {"key1": "value1", "key2": "value2"}
+  mock_context.credential_service = DummyCredentialService()
 
   return mock_context
 
@@ -32,3 +42,9 @@ def test_state_content(mock_invocation_context):
   assert isinstance(state, MappingProxyType)
   assert state["key1"] == "value1"
   assert state["key2"] == "value2"
+
+
+def test_credential_service(mock_invocation_context):
+  readonly_context = ReadonlyContext(mock_invocation_context)
+  assert readonly_context.credential_service is not None
+  assert isinstance(readonly_context.credential_service, BaseCredentialService)