}

    @Test
    public void test_trimHistoryAllUserMessages() {
        final ChatSession session = new ChatSession();
        session.addUserMessage("User 1");
        session.addUserMessage("User 2");
        session.addUserMessage("User 3");
        session.addUserMessage("User 4");

        // All user messages - trimming to 2 starts at index 2 which is user, no skip needed
        session.trimHistory(2);

                }
                return defaultValue;
            }
        });

        final ChatSession session = new ChatSession();
        session.addUserMessage("Q1");
        session.addAssistantMessage("A1");
        session.addUserMessage("Q2");
        session.addAssistantMessage("A2");

        final List<LlmMessage> history = chatClient.testExtractHistory(session);
        assertEquals(4, history.size());