code: @Test public void ifContextIsNotFoundHelperMissingIsUsed() throws IOException {
    String string="{{hello}} {{link_to world}}";
    String context="{ hello: Hello, world: world }";
    Hash helpers=$(Handlebars.HELPER_MISSING,new Helper<String>(){
      @Override public CharSequence apply(    final String context,    final Options options) throws IOException {
        return new Handlebars.SafeString("<a>" + context + "</a>");
      }
    }
  );
    shouldCompileTo(string,context,helpers,"Hello <a>world</a>");
  }
  