session.setMessages(null);
        session.trimHistory(5);
        // Should not throw exception
        assertTrue(true);
    }

    @Test
    public void test_sessionIdIsUnique() {
        final ChatSession session1 = new ChatSession();
        final ChatSession session2 = new ChatSession();
        assertFalse(session1.getSessionId().equals(session2.getSessionId()));
    }