I'm not sure why my answer is wrong, and I'm not sure what to change in my expected message line.

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
    public void restockingWithDifferentItemsIsNotAllowed() throws Exception {
        thrown.expect(IllegalArgumentException.class);
        thrown.expectMessage("Cannot be restocked with this item");
        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);
    }
}

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));
        }
    }

}

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;
    }
}