GZIPResponseWrapper test = new GZIPResponseWrapper(response);
ServletOutputStream servletOutput = test.getOutputStream();
assertEquals(org.apache.hadoop.hbase.rest.filter.GZIPResponseStream.class,
servletOutput.getClass());
test.reset();
verify(response).setHeader("Content-Encoding", null);
when(response.isCommitted()).thenReturn(true);
servletOutput = test.getOutputStream();
assertEquals(out.getClass(), servletOutput.getClass());