SortedArrayList中的Java.lang.AssertionError

Question

So I'm making an Contact Manager App in Android. My professor send us a JUnit test so we can know if our code is working correctly. Now every method has passed the test except the iterator test which fails the test. It appears to be a java.lang.AssertionError and I cant seem to figure out a way of fixing it. If you could see the error and point it out to me would be awesome.

Thanks in advance

Answer 1

You haven't implemented your iterator(int) method

@Override
public Iterator<E> iterator(int index) 
{
    // TODO Auto-generated method stub
    return new ListIterator<E>();
}

to do anything about the index. So in your test

@Test
public void testIteratorInt() {
    Iterator<String> iter = this.list.iterator(0);
    assertTrue(iter.hasNext());
    assertTrue(iter.next().equals("Amy"));

    iter = this.list.iterator(2);
    assertTrue(iter.hasNext());
    assertTrue(iter.next().equals("Bob"));
}

the ListIterator returned still starts off pointing to the first element, instead of the third, which is Bob .

You could simply move the iterator forward twice and then test

iter.next();
iter.next();
assertTrue(iter.next().equals("Bob"));

Or actually implement the iterator(int) method as you see fit.

Answer 2

The error is coming off the second assert in testIteratorInt :

@Test
public void testIteratorInt() {
    Iterator<String> iter = this.list.iterator(0);
    assertTrue(iter.hasNext());
    assertTrue(iter.next().equals("Amy"));

    iter = this.list.iterator(2);
    assertTrue(iter.hasNext());    
    assertTrue(iter.next().equals("Bob"));//ASSERT ERROR THROWN HERE

}

The iterator(int index) method needs to be implemented such that it sets the current position when it's passed in like the above unit test. Something like this should work:

@Override
public Iterator<E> iterator(int index) {
    ListIterator<E> iter = new ListIterator<E>();
    iter.currentPosition = index;
    return iter;
}

Tested and working on my machine.