final String result = chatClient.testBuildAssistantHistoryContent(msg, "full", 500, 500);
        assertEquals("Full response text here.", result);
    }

    @Test
    public void test_buildAssistantHistoryContent_none() {
        final ChatMessage msg = ChatMessage.assistantMessage("Any content");
        final String result = chatClient.testBuildAssistantHistoryContent(msg, "none", 500, 500);
        assertNull(result);
    }