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Java Unit Testing in Java What to Test Ruler of rules

Posted by Makimi Meyer
Makimi Meyer
17,421 Points

Rule of rules

Okay, so now I'd like to upgrade that previous test we wrote restockingWithDifferentItemsIsNotAllowed to check that we are getting the appropriate error message.

PS. If you are stuck, refresh your memory with the pattern used in overstockingNotAllowed .

I have no idea what is wrong. Could you help me?

com/teamtreehouse/vending/BinTest.java 
package com.teamtreehouse.vending;

import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;

import static org.junit.Assert.*;

public class BinTest {

    private Bin bin ;

    @Rule
    public ExpectedException thrown = ExpectedException.none();


    @Before
    public void setUp() throws Exception {
        bin = new Bin(10);
    }

    @Test(expected = IllegalArgumentException.class)
    public void restockingWithDifferentItemsIsNotAllowed() throws Exception {
        bin.restock("Cheetos", 1, 100, 50);
        bin.restock("Doritos", 1, 100, 50);
    }

    @Test
    public void whenEmptyPriceIsZero() throws Exception {
        assertEquals(0, bin.getItemPrice());
    }

    @Test
    public void whenEmptyNameIsNull() throws Exception {
        assertNull(bin.getItemName());
    }

    @Test
    public void overstockingNotAllowed() throws Exception {
        thrown.expect(IllegalArgumentException.class);
        thrown.expectMessage("There are only 10 spots left");

        bin.restock("Fritos", 2600, 100, 50);
    }

  @Test(expected = IllegalArgumentException.class)
    public void restockingWithDifferentItemsIsNotAllowed() throws Exception {
        bin.restock("Cheetos", 1, 100, 50);
        bin.restock("Doritos", 1, 100, 50);
    }


Ask to answer

}
com/teamtreehouse/vending/Bin.java 
package com.teamtreehouse.vending;

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;

public class Bin {
    private final BlockingQueue<Item> items;

    public Bin(int maxItems) {
        items = new ArrayBlockingQueue<>(maxItems);
    }

    public boolean isEmpty() {
        return items.isEmpty();
    }

    public int getAvailableSlots() {
        return items.remainingCapacity();
    }

    public String getItemName() {
        if (isEmpty()) return null;
        return items.peek().getName();
    }

    public int getItemPrice() {
        if (isEmpty()) {
            return 0;
        }
        return items.peek().getRetailPrice();
    }

    public Item release() {
        return items.poll();
    }

    public void restock(String name, int amount, int wholesalePrice, int retailPrice) {
        if (!isEmpty() && !name.equalsIgnoreCase(getItemName())) {
            throw new IllegalArgumentException(String.format("Cannot restock %s with %s", getItemName(), name));
        }
        if (amount > getAvailableSlots()) {
            throw new IllegalArgumentException(String.format("There are only %d spots left", getAvailableSlots()));
        }
        for (int i = 0; i < amount; i++) {
            items.add(new Item(name, wholesalePrice, retailPrice));
        }
    }

}
com/teamtreehouse/vending/Item.java 
package com.teamtreehouse.vending;

public class Item {
    private final String name;
    private final int wholesalePrice;
    private final int retailPrice;

    public Item(String name, int wholesalePrice, int retailPrice) {
        this.name = name;
        this.wholesalePrice = wholesalePrice;
        this.retailPrice = retailPrice;
    }

    public String getName() {
        return name;
    }

    public int getWholesalePrice() {
        return wholesalePrice;
    }

    public int getRetailPrice() {
        return retailPrice;
    }
}

2 Answers

Mihai Craciun
Mihai Craciun
13,520 Points
Mihai Craciun
Mihai Craciun
13,520 Points

You have to modify not to rewrite the existing restockingWithDifferentItemsIsNotAllowed() method so it will expect the exact message you expect. If you look closely you already have the method you just have to complete it. In general message is "Cannot restock %s with %s" so your method should expect the message "Cannot restock Cheetos with Doritos". Dont forget to delete the expected element from the @Test annotation.

In the end the method should look like this:

 @Test
    public void restockingWithDifferentItemsIsNotAllowed() throws Exception {
        thrown.expectMessage("Cannot restock Cheetos with Doritos");
        bin.restock("Cheetos", 1, 100, 50);
        bin.restock("Doritos", 1, 100, 50);

    }
Ethan Hewson
Ethan Hewson
4,267 Points

Hi, I tried having this: @Test public void restockingWIthDifferentItemsIsNotAllowed() throws Exception { thrown.expect(IllegalArgumentException); thrown.expect("Cannot restock Cheetos with Doritos"); bin.restock("Cheetos", 1, 100, 50); bin.restock("Doritos", 1, 100, 50);

}

and the code did not work. But then I removed the "thrown.expect(IllegalArgumentException);" and it worked. Could you tell me why it did not work with the exception specified?

Makimi Meyer
Makimi Meyer
17,421 Points
Makimi Meyer
Makimi Meyer
17,421 Points

Thank you so much. I followed the video as much I can, but sometimes video and objective are different( I might feel...)

Anyway, thank you again!

Mihai Craciun
Mihai Craciun
13,520 Points
Mihai Craciun
Mihai Craciun
13,520 Points

You're welcome! I'm glad I could help. Happy coding! :)