@Test
public void testGetUserRoles() {

    Set<Role> roles = engine.getUserRoles(username);
    assertFalse(roles.isEmpty());
    Set<Resource> roleIds = roles.stream()
            .map(Thing::getResource)
            .collect(Collectors.toSet());
    assertTrue(roleIds.contains(VALUE_FACTORY.createIRI(userRoleId)));
    assertTrue(roleIds.contains(VALUE_FACTORY.createIRI(adminRoleId)));
}