@Test
public void getsHttpHeadersFromServletRequest() throws Exception {

    Map<String, List<String>> httpHeaders = new HashMap<>();
    httpHeaders.put("content-type", Arrays.asList("text/plain"));
    httpHeaders.put("content-length", Arrays.asList("100"));
    configureHttpHeadersInServletRequest(httpHeaders);
    ServletContainerRequest servletContainerRequest = ServletContainerRequest.create(httpServletRequest);
    assertEquals("text/plain", servletContainerRequest.getRequestHeaders().getFirst("content-type"));
    assertEquals("100", servletContainerRequest.getRequestHeaders().getFirst("content-length"));
}