@Test
public void testEscape() {

  String orig = "\uD850\uDDAC成功";
  String escaped = CleanXMLStreamWriter.escapeCharacters(orig);
  assertEquals(orig, escaped);
  orig = "\uDBC0\uDCDF am 25 April 1868";
  escaped = CleanXMLStreamWriter.escapeCharacters(orig);
  assertEquals(orig, escaped);
  orig = "蘇\uD849\uDF67";
  escaped = CleanXMLStreamWriter.escapeCharacters(orig);
  assertEquals(orig, escaped);
}