CODEWITHSUNDEEP
javajunit
Marijus
Marijus

Reputation: 4375

JUnit test. Creating a list affects other list's size. Really really weird

So here's my test : 

@Test
public void returnsAllItemsInStock() {
    List<Item> demoItems = new ArrayList<Item>();

    Item demoItemOne = new Item();
    demoItemOne.setQuantity(0);

    Item demoItemTwo = new Item();
    demoItemTwo.setQuantity(17);

    demoItems.add(demoItemOne);
    demoItems.add(demoItemTwo); // List size currently 2

    Mockito.when(itemRepository.findAll()).thenReturn(demoItems);

    List<Item> items = inventoryService.allItemsInStock();// Here demoItems size somehow changes to 1

    Assert.assertEquals("List's size expected not to match", items.size(), demoItems.size()); // This one should fail because sizes shouldn't be equal, but they are..
}

Here's my service implementation:

@Override
@Transactional
public List<Item> allItemsInStock() {
    List<Item> items = new ArrayList<Item>();
    items = (List<Item>) itemRepository.findAll();

    for (Iterator<Item> it = items.iterator(); it.hasNext();) {
        Item item = it.next();
        if (item.getQuantity() <= 0) {
            it.remove();
        }
    }


    return items;
}

I explained problem in the comments. check my test.

Upvotes: 0

Views: 77

Answers (2)

javaPlease42
javaPlease42

Reputation: 4973

I ran your Test method with your implementation and your only assert was successful:

import java.util.ArrayList;
import java.util.List;

import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.powermock.modules.junit4.PowerMockRunner; 



@RunWith(PowerMockRunner.class)
public class InventoryServiceTest {

    @Mock
    private ItemRepository itemRepository;

    @InjectMocks
    private InventoryService inventoryService;

    @Test
    public void returnsAllItemsInStock() {
        List<Item> demoItems = new ArrayList<Item>();

        Item demoItemOne = new Item();
        demoItemOne.setQuantity(0);

        Item demoItemTwo = new Item();
        demoItemTwo.setQuantity(17);

        demoItems.add(demoItemOne);
        demoItems.add(demoItemTwo); // List size currently 2

        Mockito.when(itemRepository.findAll()).thenReturn(demoItems);

        List<Item> items = inventoryService.allItemsInStock();// Here demoItems size somehow changes to 1

        Assert.assertEquals("List's size expected not to match", items.size(), demoItems.size()); // This one should fail because sizes shouldn't be equal, but they are..
    }

}

Because yes they both have a size of one: enter image description here

Upvotes: 0

Dave Newton
Dave Newton

Reputation: 160271

demoItems list changes because you're using it as your list of items: you return demoItems from the service's findAll() method.

You then remove items with quantity zero. They're the same list. Not weird at all.

Upvotes: 2

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