assertEquals("Some content here that is quite long enough to be truncated.", result);
    }

    // ========== additional truncated tests ==========

    @Test
    public void test_truncated_nullContent() {
        final ChatMessage msg = ChatMessage.assistantMessage(null);
        final String result = chatClient.testBuildAssistantHistoryContent(msg, "truncated", 500, 500);
        assertNull(result);
    }