@Test public void test() throws IOException, ServletException { Date now = new Date(); GwtCacheFilter filter = new GwtCacheFilter(); HttpServletRequest request = new MockHttpServletRequest("GET", "/profile.nocache.js"); MockHttpServletResponse response = new MockHttpServletResponse(); MockFilterChain chain = new MockFilterChain(); filter.doFilter(request, response, chain); Assert.assertTrue(response.containsHeader("Expires")); Assert.assertTrue(now.after(new Date(Long.parseLong(response.getHeader("Expires"))))); request = new MockHttpServletRequest("GET", "/profile.XXXXXXX.cache.js"); response = new MockHttpServletResponse(); chain = new MockFilterChain(); filter.doFilter(request, response, chain); Assert.assertTrue(response.containsHeader("Expires")); Assert.assertTrue(now.before(new Date(Long.parseLong(response.getHeader("Expires"))))); }