Principal p = getTestPrincipal();
String childID = userMgr.createUser(p.getName(), buildPassword(p), p, uPath).getID();
try {
Authorizable child = uMgr.getAuthorizable(childID);
Impersonation impers = ((User) child).getImpersonation();
Principal himselfP = uMgr.getAuthorizable(uID).getPrincipal();
assertFalse(impers.allows(buildSubject(himselfP)));
impers.grantImpersonation(himselfP);
fail("A non-administrator user should not be allowed modify Impersonation of a child user.");
} catch (AccessDeniedException e) {
// success
}