assertThat(i.next(), is("bbb"));
        assertThat(i.next(), is("ccc"));
        assertThat(i.next(), is("aaa"));
        lru.put("ddd", "444");
        assertThat(lru.size(), is(3));
        assertThat(lru.get("bbb"), is(nullValue()));
        i = lru.keySet().iterator();
        assertThat(i.next(), is("ccc"));
        assertThat(i.next(), is("aaa"));
        assertThat(i.next(), is("ddd"));

            }
          }
        };

    assertTrue(iter.hasNext());
    assertEquals(0, (int) iter.next());

    // verify idempotence of hasNext()
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertEquals(1, (int) iter.next());

    assertFalse(iter.hasNext());

    // Make sure computeNext() doesn't get invoked again

            }
          }
        };

    assertTrue(iter.hasNext());
    assertEquals(0, (int) iter.next());

    // verify idempotence of hasNext()
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertEquals(1, (int) iter.next());

    assertFalse(iter.hasNext());

    // Make sure computeNext() doesn't get invoked again

    bimap.put(1, "one");
    bimap.put(2, "two");
    bimap.put(3, "three");
    Iterator<Integer> iterator = bimap.keySet().iterator();
    iterator.next();
    iterator.next();
    iterator.remove();
    iterator.next();
    iterator.remove();
    assertEquals(1, bimap.size());
    assertEquals(1, bimap.inverse().size());
  }

    bimap.put(1, "one");
    bimap.put(2, "two");
    bimap.put(3, "three");
    Iterator<Integer> iterator = bimap.keySet().iterator();
    iterator.next();
    iterator.next();
    iterator.remove();
    iterator.next();
    iterator.remove();
    assertEquals(1, bimap.size());
    assertEquals(1, bimap.inverse().size());
  }

        // Act
        assertTrue(it.hasNext());
        assertEquals("first", it.next().getName()); // initial
        assertTrue(it.hasNext());
        FileEntry next = it.next();

        // Assert: "bad" was skipped due to filter exception, "good" returned
        assertNotNull(next);
        assertEquals("good", next.getName());
        assertFalse(it.hasNext());
        verify(tree, times(1)).release();
    }

    assertEquals(o1, three.next().target);
    assertFalse(three.hasNext());

    three = registry.getSubscribers("");

    registry.unregister(s2);

    assertEquals(s1, three.next().target);
    assertEquals(s2, three.next().target);
    assertEquals(o1, three.next().target);
    assertFalse(three.hasNext());

    Iterator<Subscriber> two = registry.getSubscribers("");
    assertEquals(s1, two.next().target);

    }

    /**
     * Returns true if a next page exists.
     *
     * @return True if a next page exists.
     */
    public boolean isExistNextPage() {
        return existNextPage;
    }

    /**
     * Sets whether a next page exists.
     *
     * @param existNextPage True if a next page exists.
     */
    public void setExistNextPage(final boolean existNextPage) {

    }

    /**
     * Checks if there is a next page.
     * @return True if a next page exists, false otherwise.
     */
    public boolean isExistNextPage() {
        return existNextPage;
    }

    /**
     * Sets the existence of a next page.
     * @param existNextPage True if a next page exists.
     */
    public void setExistNextPage(final boolean existNextPage) {

            assertEquals(second, referralData.next());
            assertEquals(referralData, second.next());

            referralData.append(third);
            assertEquals(third, referralData.next());
            assertEquals(second, third.next());
            assertEquals(referralData, second.next());
        }

        @Test
        @DisplayName("Should handle next() correctly")
        void testNext() {