public void testGZIPResponseStream() throws IOException {
HttpServletResponse httpResponce = mock(HttpServletResponse.class);
ServletOutputStream out = mock(ServletOutputStream.class);
when(httpResponce.getOutputStream()).thenReturn(out);
GZIPResponseStream test = new GZIPResponseStream(httpResponce);
verify(httpResponce).addHeader("Content-Encoding", "gzip");
test.close();
test.resetBuffer();
verify(httpResponce).setHeader("Content-Encoding", null);
}