@Test public void testHeaderFooterThreadContext() throws Exception {
  final PatternLayout layout=PatternLayout.newBuilder().withPattern("%d{UNIX} %m").withConfiguration(ctx.getConfiguration()).withHeader("${ctx:header}").withFooter("${ctx:footer}").build();
  ThreadContext.put("header","Hello world Header");
  ThreadContext.put("footer","Hello world Footer");
  final byte[] header=layout.getHeader();
  assertNotNull("No header",header);
  assertTrue("expected \"Hello world Header\", actual " + Strings.dquote(new String(header)),new String(header).equals(new String("Hello world Header")));
}