assertFalse(keyManager.hasSessionKey(sessionId), "Key should be removed");
        assertNull(keyManager.getSessionKey(sessionId), "Should not retrieve removed key");
    }

    @Test
    public void testKeyIsolation() {
        String sessionId1 = "session-1";
        String sessionId2 = "session-2";

        byte[] key1 = new byte[16];
        byte[] key2 = new byte[16];
        new SecureRandom().nextBytes(key1);