assertThrows(IllegalArgumentException.class, () -> escapeAsString(SIMPLE_ESCAPER, test));
  }

  @SuppressWarnings("nullness") // test of bogus call
  public void testNullInput() {
    UnicodeEscaper e = SIMPLE_ESCAPER;
    assertThrows(NullPointerException.class, () -> e.escape((String) null));
  }

  public void testBadStrings() {
    UnicodeEscaper e = SIMPLE_ESCAPER;