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Java Unit Testing in Java What to Test Test the running total

Jonathan Hector
Jonathan Hector
5,225 Points

Can't seem to finish the challenge

Is there a problem on the server or is it an issue with my code?

package com.teamtreehouse.vending;

import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.*;

public class VendingMachineTest {
    private VendingMachine machine;

    public class NotifierSub implements Notifier {

        public void onSale(Item item) {

    public void setUp() throws Exception {
        Notifier notifier = new NotifierSub();
        machine = new VendingMachine(notifier, 10, 10, 10);
        machine.restock("A1", "Twinkies", 10, 30, 75);

    public void vendingWhenStockedReturnsItem() throws Exception {

        Item item = machine.vend("A1");

        assertEquals("Twinkies", item.getName());

  public void onSuccessfulVendItemTotalIsIncremented(){
    assertEquals(1, machine.getRunningSalesTotal());
package com.teamtreehouse.vending;

public class VendingMachine {
    private final Notifier notifier;
    private final AbstractChooser chooser;
    private final Creditor creditor;
    private final Bin[][] bins;
    private int runningSalesTotal;

    public VendingMachine(Notifier notifier, int rowCount, int columnCount, int maxItemsPerBin) {
        this.notifier = notifier;
        chooser = new AlphaNumericChooser(rowCount, columnCount);
        creditor = new Creditor();
        runningSalesTotal = 0;
        bins = new Bin[rowCount][columnCount];
        for (int row = 0; row < rowCount; row++) {
            for (int col = 0; col < columnCount; col++) {
                bins[row][col] = new Bin(maxItemsPerBin);

    public void addMoney(int money) {

    public int refundMoney() {
        return creditor.refund();

    public Item vend(String input) throws InvalidLocationException, NotEnoughFundsException {
        Bin bin = binByInput(input);
        int price = bin.getItemPrice();
        runningSalesTotal += price;
        Item item = bin.release();
        return item;

    public int getRunningSalesTotal() {
        return runningSalesTotal;

    public void restock(String input, String name, int amount, int wholesalePrice, int retailPrice) throws InvalidLocationException {
        Bin bin = binByInput(input);
        bin.restock(name, amount, wholesalePrice, retailPrice);

    private Bin binByInput(String input) throws InvalidLocationException {
        AbstractChooser.Location location = chooser.locationFromInput(input);
        return bins[location.getRow()][location.getColumn()];


1 Answer

Sashreek Siddhartha Reddy Dammu
Sashreek Siddhartha Reddy Dammu
410 Points

getRunningSalesTotal() returns the total sales amount not quantity. Since, you set the cost of one "Twinkie" as 75, after you vend one Twinkie, the sales total becomes 75 not 1. Change your assertEquals statement to,

assertEquals(75, machine.getRunningSalesTotal());