}
public void doUpdateStateObserver_OneNullInvariant()
{
Expr e = new Expr("Pine");
StateObserverInfo soInfo = new StateObserverInfo(soPine, Type.INTEGER, e);
main.doAddStateObserver(soInfo);
StateObserver so = new StateObserver(soInfo);
StateObserverInfo newSoInfo = new StateObserverInfo(soPine, Type.INTEGER, Expr.EMPTY);
main.doUpdateStateObserver(so, newSoInfo);
assertTrue(so.name().equals(soPine));
assertTrue(so.type().equals(Type.INTEGER));
assertTrue(so.invariant().equals(Expr.EMPTY));
}