final Date inTenMinutes = new Date(now.getTime() + 600 * 1000L);
impl = new CachingExec(mockBackend, new BasicHttpCache(), CacheConfig.DEFAULT);
final HttpRequestWrapper req1 = HttpRequestWrapper.wrap(new HttpGet("http://foo.example.com/"));
req1.addHeader("If-Modified-Since", DateUtils.formatDate(oneHourAgo));
final HttpRequestWrapper req2 = HttpRequestWrapper.wrap(new HttpGet("http://foo.example.com/"));
req2.addHeader("If-Modified-Since", DateUtils.formatDate(oneHourAgo));
final HttpResponse resp1 = new BasicHttpResponse(HttpVersion.HTTP_1_1, HttpStatus.SC_NOT_MODIFIED, "Not modified");
resp1.setHeader("Date", DateUtils.formatDate(now));
resp1.setHeader("Cache-control", "max-age=600");
resp1.setHeader("Expires", DateUtils.formatDate(inTenMinutes));