assertNotNull(defaultRoles, "Default roles should not be null");
    }

    /**
     * Test list isolation during concurrent updates.
     */
    @Test
    public void test_listIsolation_duringConcurrentUpdates() throws Exception {
        List<String> originalGroups = new ArrayList<>();
        originalGroups.add("original-group");

        List<String> copiedGroups = new ArrayList<>(originalGroups);