@Test
  public void testDoFilterGzipResponseCompression() throws Exception {
    MockHttpServletRequest request =
        new MockHttpServletRequest(HttpMethod.POST.name(), "http://localhost:8080/gzip");
    request.addHeader(HttpHeaders.ACCEPT_ENCODING, "gzip");

    MockHttpServletResponse response = new MockHttpServletResponse();
    MockFilterChain filterChain =
        new MockFilterChain(
            servlet,
            new GzipServletFilter(),
            new OncePerRequestFilter() {
              @Override
              protected void doFilterInternal(
                  HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
                  throws ServletException, IOException {
                response.getOutputStream().write("Should be compressed".getBytes());
              }
            });
    filterChain.doFilter(request, response);

    ByteArrayOutputStream unzippedStream = new ByteArrayOutputStream();
    StreamUtils.copy(
        new GZIPInputStream(new ByteArrayInputStream(response.getContentAsByteArray())),
        unzippedStream);
    String unzipped = new String(unzippedStream.toByteArray());

    Assert.assertEquals(unzipped, "Should be compressed");
  }
  @Test
  public void testDoFilterNoCompression() throws Exception {
    MockHttpServletRequest request =
        new MockHttpServletRequest(HttpMethod.POST.name(), "http://localhost:8080/gzip");

    MockHttpServletResponse response = new MockHttpServletResponse();
    MockFilterChain filterChain =
        new MockFilterChain(
            servlet,
            new GzipServletFilter(),
            new OncePerRequestFilter() {
              @Override
              protected void doFilterInternal(
                  HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
                  throws ServletException, IOException {
                response.getOutputStream().write("Should be compressed".getBytes());
              }
            });
    filterChain.doFilter(request, response);

    String unzipped = new String(response.getContentAsByteArray());
    Assert.assertEquals(unzipped, "Should be compressed");
  }