assertThat(escapeAsString(e, test)).isEqualTo(expected);
  }

  public void testTrailingHighSurrogate() {
    String test = "abc" + Character.MIN_HIGH_SURROGATE;
    assertThrows(IllegalArgumentException.class, () -> escapeAsString(NOP_ESCAPER, test));
    assertThrows(IllegalArgumentException.class, () -> escapeAsString(SIMPLE_ESCAPER, test));
  }