@Test
  public void splitStringWithFilterTest() {
    ArrayList<String> result = new ArrayList<>();
    Utils.splitString("a,b,c", ",", null, result);
    assertEquals(Arrays.asList("a", "b", "c"), result);

    result.clear();
    Utils.splitString(" A, B , C  ", ",", (item -> item.toLowerCase(Locale.ROOT).trim()), result);
    assertEquals(Arrays.asList("a", "b", "c"), result);
  }
Tests for {@link Utils#splitString(String, String)}.
ambry-utils/src/test/java/com/github/ambry/utils/UtilsTest.java