public void testGetCop() throws PostServiceNotSetException {
        System.out.println("getCop");
        try {
            int numberOfGenerators = 3;
            int numberOfLoadsForGenerator = 4;
            int R = 1;
            double xmean = 0.5;
            double delta = 0.1;
            PowerGrid instance = new PowerGrid(numberOfGenerators, numberOfLoadsForGenerator, R, xmean, delta);

            System.out.println("Instance to string:\n" + instance.toStringFile());

            System.out.println("Instance is initializated: " + instance.isInitializated());

            // note: toStringFile does NOT work for these NodeArguments.
            System.out.println("COP:\n" + instance.getCop().toStringFile());

            Athena solver = new Athena(instance.getCop(), "min", "sum");
            solver.setIterationsNumber(100);
            solver.solve();
            solver.conclude();
            System.out.println("Value: " + instance.getCop().actualValue());


        } catch (IllegalArgumentException ex) {
            System.out.println("Illegal argument Exception");
        } catch (NoMoreGeneratorsException ex) {
            System.out.println("No more generators Exception");
        } catch (InitializatedException ex) {
            System.out.println("Initializated Exception");
        } catch (UnInitializatedException ex) {
            System.out.println("UnInitializated Exception");
        } catch (VariableNotSetException ex) {
            System.out.println("Variable not set");
        }

    }