MockFilterChain chain = new MockFilterChain();
MockHttpServletRequest request = new MockHttpServletRequest();
MockHttpServletResponse response = new MockHttpServletResponse();
config.addInitParameter("expiresSeconds", "123");
CacheControlHeaderFilter filter = new CacheControlHeaderFilter();
filter.init(config);
filter.doFilter(request, response, chain);
assertEquals("private, max-age=123", response.getHeader("Cache-Control"));
}