@Test
 public void httpHeaderNameCasingIsPreserved() throws Exception {
   final String headerName = "Header1";
   response.addHeader(headerName, "value1");
   Collection<String> responseHeaders = response.getHeaderNames();
   assertNotNull(responseHeaders);
   assertEquals(1, responseHeaders.size());
   assertEquals(
       "HTTP header casing not being preserved", headerName, responseHeaders.iterator().next());
 }