EscaperAsserts.assertBasic(escaper);
    String s = "\0\n\t\\az09~\uD800\uDC00\uFFFF";
    assertWithMessage("null escaper should have no effect").that(escaper.escape(s)).isEqualTo(s);
  }

  public void testBuilderInitialStateNoReplacement() {
    // Unsafe characters aren't modified by default (unsafeReplacement == null).
    Escaper escaper = Escapers.builder().setSafeRange('a', 'z').build();