public abstract boolean compare(A actual, E expected);
@Test
  public void testTransforming_actual_compare_nullTransformedValues() {
    assertThat(HYPHEN_INDEXES.compare("mailing-list", null)).isFalse();
    assertThat(HYPHEN_INDEXES.compare("forum", 7)).isFalse();
    assertThat(HYPHEN_INDEXES.compare("forum", null)).isTrue();
  }