.add(LONG_NAME, null)
            .addValue("z")
            .addValue("")
            .addValue(null)
            .add(SHORT_NAME, Arrays.asList("A"))
            .add(LONG_NAME, Arrays.asList("B"))
            .add(SHORT_NAME, Arrays.asList())
            .add(LONG_NAME, Arrays.asList())
            .addValue(Arrays.asList("C"))
            .addValue(Arrays.asList())

        });
  }

  @Before
  public void init() {
    mapCache.clear();
  }

  @Test
  public void testKeySetIterator() {
    mapCache.put("A", "A_value");
    mapCache.put("B", "B_value");
    mapCache.put("C", "C_value");

    assertThat(mapCache.unmodifiableKeySet()).hasSize(3);
    for (String key : mapCache.unmodifiableKeySet()) {