// update
admin.updateCredential("dimuthu", "password", "topsecret");
assertFalse(admin.authenticate("dimuthu", "credential"));
assertTrue(admin.authenticate("dimuthu", "password"));
String[] names = admin.listUsers("*", 100);
assertEquals(3, names.length);
String[] roleNames = admin.getRoleNames();
assertEquals(4, roleNames.length);