fix test

tests/agent_test.py

@@ -1606,6 +1606,13 @@ def test_agent_with_knowledge_sources():
 def test_agent_with_knowledge_sources_works_with_test():
     content = "Brandon's favorite color is red and he likes Mexican food."
     string_source = StringKnowledgeSource(content=content)
+
+    with patch(
+        "crewai.knowledge.storage.knowledge_storage.KnowledgeStorage"
+    ) as MockKnowledge:
+        mock_knowledge_instance = MockKnowledge.return_value
+        mock_knowledge_instance.sources = [string_source]
+
         agent = Agent(
             role="test role",
             goal="test goal",
@@ -1617,6 +1624,7 @@ def test_agent_with_knowledge_sources_works_with_test():
         agent.create_agent_executor()
         agent_copy = agent.copy()
 
+        # Test that all properties were copied correctly
         assert agent_copy.role == agent.role
         assert agent_copy.goal == agent.goal
         assert agent_copy.backstory == agent.backstory