@Test
  public void testIsNotGzipCompressedHttpBadRequestStatus() throws Exception {
    GzipTester tester = new GzipTester(testingdir, compressionType);

    // Test error code 400
    FilterHolder holder = tester.setContentServlet(HttpErrorServlet.class);
    holder.setInitParameter("mimeTypes", "text/plain");

    try {
      tester.start();
      tester.assertIsResponseNotGzipCompressedAndEqualToExpectedString("error message", -1, 400);
    } finally {
      tester.stop();
    }
  }