@Test
public void testGetUserRolesInOneEngine() {

    Set<Role> roles = engineManager.getUserRoles(ERROR, "user");
    verify(engine, times(0)).getUserRoles("user");
    assertTrue(roles.isEmpty());
    roles = engineManager.getUserRoles(engine.getEngineName(), "user");
    verify(engine).getUserRoles("user");
    assertEquals(1, roles.size());
}