@Test
    void testDeep() {
        HitGroup grandParent = new HitGroup();
        grandParent.add(new Hit("a"));
        HitGroup parent = new HitGroup();
        parent.add(new Hit("b"));
        HitGroup child = new HitGroup();
        child.add(new Hit("c"));
        HitGroup grandChild = new HitGroup();
        grandChild.add(new Hit("d"));
        child.add(grandChild);
        child.add(new Hit("e"));
        parent.add(child);
        parent.add(new Hit("f"));
        grandParent.add(parent);
        grandParent.add(new Hit("g"));

        Iterator<Hit> it = grandParent.deepIterator();
        assertTrue(it.hasNext());
        assertEquals("a", it.next().getId().toString());
        assertTrue(it.hasNext());
        assertEquals("b", it.next().getId().toString());
        assertTrue(it.hasNext());
        assertEquals("c", it.next().getId().toString());
        assertTrue(it.hasNext());
        assertEquals("d", it.next().getId().toString());
        assertTrue(it.hasNext());
        assertEquals("e", it.next().getId().toString());
        assertTrue(it.hasNext());
        assertEquals("f", it.next().getId().toString());
        assertTrue(it.hasNext());
        assertEquals("g", it.next().getId().toString());
        assertFalse(it.hasNext());
    }
Ensure that the {@link DeepHitIterator} works as intended.

@author havardpe
container-search/src/test/java/com/yahoo/search/result/test/DeepHitIteratorTestCase.java