}

  public void testHigherEntry() {
    assertThat(create().higherEntry("a")).isNull();
  }

  public void testHigherKey() {
    assertThat(create().higherKey("a")).isNull();
  }

  public void testLastEntry() {
    assertThat(create().lastEntry()).isNull();
  }

  public void testLastKey() {
    NavigableMap<String, Integer> map = create();
    map.put("a", 1);

  private static final Object OBJECT = new Object();

  public void testNewReference() throws Exception {
    assertThat(Atomics.newReference().get()).isNull();
  }

  public void testNewReference_withInitialValue() throws Exception {
    assertThat(Atomics.newReference(null).get()).isNull();
    assertEquals(OBJECT, Atomics.newReference(OBJECT).get());
  }

  public void testNewReferenceArray_withLength() throws Exception {

    ValueReference<Object, Object> valueRef = map.newValueReference(entry, value, 1);
    entry.setValueReference(valueRef);

    assertThat(segment.get(key, hash)).isNull();

    // count == 0
    table.set(index, entry);
    assertThat(segment.get(key, hash)).isNull();
    assertThat(segment.containsKey(key, hash)).isFalse();
    assertThat(segment.containsValue(value)).isFalse();

    // count == 1

    ValueReference<Object, Object> valueRef = map.newValueReference(entry, value, 1);
    entry.setValueReference(valueRef);

    assertThat(segment.get(key, hash)).isNull();

    // count == 0
    table.set(index, entry);
    assertThat(segment.get(key, hash)).isNull();
    assertThat(segment.containsKey(key, hash)).isFalse();
    assertThat(segment.containsValue(value)).isFalse();

    // count == 1

    assertThat(map.get(Integer.class)).isNull();
    assertThat(map.getInstance(Integer.class)).isNull();

    map.put(Long.class, null);
    assertThat(map.get(Long.class)).isNull();
    assertThat(map.getInstance(Long.class)).isNull();
  }

  public void testPrimitiveAndWrapper() {
    assertThat(map.getInstance(int.class)).isNull();
    assertThat(map.getInstance(Integer.class)).isNull();

    segment.setValueForTesting(entry, value);

    assertThat(segment.get(key, hash)).isNull();

    // count == 0
    segment.setTableEntryForTesting(index, entry);
    assertThat(segment.get(key, hash)).isNull();
    assertFalse(segment.containsKey(key, hash));
    assertFalse(segment.containsValue(value));

    // count == 1
    segment.count++;

    segment.setValueForTesting(entry, value);

    assertThat(segment.get(key, hash)).isNull();

    // count == 0
    segment.setTableEntryForTesting(index, entry);
    assertThat(segment.get(key, hash)).isNull();
    assertFalse(segment.containsKey(key, hash));
    assertFalse(segment.containsValue(value));

    // count == 1
    segment.count++;

    assertEquals(TestEnum.HONDA, converter.convert("HONDA"));
    assertEquals(TestEnum.POODLE, converter.convert("POODLE"));
    assertThat(converter.convert(null)).isNull();
    assertThat(converter.reverse().convert(null)).isNull();
  }

  public void testStringConverter_convertError() {
    Converter<String, TestEnum> converter = Enums.stringConverter(TestEnum.class);

    assertThat(map.containsKey(one)).isFalse();
    assertThat(map.containsValue(one)).isFalse();
    assertThat(map.putIfAbsent(two, three)).isNull();
    assertThat(map.remove(two)).isSameInstanceAs(three);
    assertThat(map.put(three, one)).isNull();
    assertThat(map.put(one, two)).isNull();

    assertThat(map).containsEntry(three, one);
    assertThat(map).containsEntry(one, two);

    assertThat(map.containsKey(one)).isFalse();
    assertThat(map.containsValue(one)).isFalse();
    assertThat(map.putIfAbsent(two, three)).isNull();
    assertThat(map.remove(two)).isSameInstanceAs(three);
    assertThat(map.put(three, one)).isNull();
    assertThat(map.put(one, two)).isNull();

    assertThat(map).containsEntry(three, one);
    assertThat(map).containsEntry(one, two);