@Test public void someFiltered() {

  array[0] = "1";
  array[1] = "one";
  array[2] = "2";
  array[3] = "two";
  array[4] = "3";
  array[5] = "three";
  Map<String, String> map = builder.filterKeys("1", "3").build(array);
  assertSize(map, 1);
  assertBaseCase(map);
  assertThat(map).containsOnly(
      entry("2", "two")
  );
  assertThat(map).hasToString(
      "UnsafeArrayMap{2=two}"
  );
  assertThat(map.get("1")).isNull();
  assertThat(map.get("2")).isEqualTo("two");
  assertThat(map.get("3")).isNull();
}