assertEquals(ChatMessage.ROLE_USER, session.getMessages().get(0).getRole());
        assertEquals("User message content", session.getMessages().get(0).getContent());
    }

    @Test
    public void test_addAssistantMessage() {
        final ChatSession session = new ChatSession();
        session.addAssistantMessage("Assistant response");

        assertEquals(1, session.getMessages().size());