/*
    * ====================================================================
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  package org.apache.hc.client5.http.impl.cache;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertNotNull;
  import static org.junit.Assert.assertNull;
  import static org.junit.Assert.assertTrue;
  
  import java.io.IOException;
  import java.util.Arrays;
  import java.util.Date;
  import java.util.Iterator;
  import java.util.List;
  
  import org.apache.hc.client5.http.auth.StandardAuthScheme;
  import org.apache.hc.client5.http.classic.ExecChain;
  import org.apache.hc.client5.http.classic.methods.HttpGet;
  import org.apache.hc.client5.http.classic.methods.HttpPost;
  import org.apache.hc.client5.http.utils.DateUtils;
  import org.apache.hc.core5.http.ClassicHttpRequest;
  import org.apache.hc.core5.http.ClassicHttpResponse;
  import org.apache.hc.core5.http.Header;
  import org.apache.hc.core5.http.HeaderElement;
  import org.apache.hc.core5.http.HttpHeaders;
  import org.apache.hc.core5.http.HttpStatus;
  import org.apache.hc.core5.http.HttpVersion;
  import org.apache.hc.core5.http.message.BasicClassicHttpRequest;
  import org.apache.hc.core5.http.message.BasicClassicHttpResponse;
  import org.apache.hc.core5.http.message.MessageSupport;
  import org.easymock.Capture;
  import org.easymock.EasyMock;
  import org.junit.Before;
  import org.junit.Test;
  
  /*
   * This test class captures functionality required to achieve unconditional
   * compliance with the HTTP/1.1 spec, i.e. all the SHOULD, SHOULD NOT,
   * RECOMMENDED, and NOT RECOMMENDED behaviors.
   */
  public class TestProtocolRecommendations extends AbstractProtocolTest {
  
      private Date now;
      private Date tenSecondsAgo;
      private Date twoMinutesAgo;
  
      @Override
      @Before
      public void setUp() {
          super.setUp();
          now = new Date();
          tenSecondsAgo = new Date(now.getTime() - 10 * 1000L);
          twoMinutesAgo = new Date(now.getTime() - 2 * 60 * 1000L);
      }
  
      /* "identity: The default (identity) encoding; the use of no
       * transformation whatsoever. This content-coding is used only in the
       * Accept-Encoding header, and SHOULD NOT be used in the
       * Content-Encoding header."
       *
       * http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.5
       */
      @Test
      public void testIdentityCodingIsNotUsedInContentEncodingHeader() throws Exception {
          originResponse.setHeader("Content-Encoding", "identity");
          backendExpectsAnyRequest().andReturn(originResponse);
          replayMocks();
          final ClassicHttpResponse result = execute(request);
          verifyMocks();
          boolean foundIdentity = false;
          final Iterator<HeaderElement> it = MessageSupport.iterate(result, HttpHeaders.CONTENT_ENCODING);
          while (it.hasNext()) {
              final HeaderElement elt = it.next();
              if ("identity".equalsIgnoreCase(elt.getName())) {
                 foundIdentity = true;
             }
         }
         assertFalse(foundIdentity);
     }
 
     /*
      * "304 Not Modified. ... If the conditional GET used a strong cache
      * validator (see section 13.3.3), the response SHOULD NOT include
      * other entity-headers."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.5
      */
     private void cacheGenerated304ForValidatorShouldNotContainEntityHeader(
             final String headerName, final String headerValue, final String validatorHeader,
             final String validator, final String conditionalHeader) throws Exception {
         final ClassicHttpRequest req1 = HttpTestUtils.makeDefaultRequest();
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Cache-Control","max-age=3600");
         resp1.setHeader(validatorHeader, validator);
         resp1.setHeader(headerName, headerValue);
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = HttpTestUtils.makeDefaultRequest();
         req2.setHeader(conditionalHeader, validator);
 
         replayMocks();
         execute(req1);
         final ClassicHttpResponse result = execute(req2);
         verifyMocks();
 
         if (HttpStatus.SC_NOT_MODIFIED == result.getCode()) {
             assertNull(result.getFirstHeader(headerName));
         }
     }
 
     private void cacheGenerated304ForStrongETagValidatorShouldNotContainEntityHeader(
             final String headerName, final String headerValue) throws Exception {
         cacheGenerated304ForValidatorShouldNotContainEntityHeader(headerName,
                 headerValue, "ETag", "\"etag\"", "If-None-Match");
     }
 
     private void cacheGenerated304ForStrongDateValidatorShouldNotContainEntityHeader(
             final String headerName, final String headerValue) throws Exception {
         cacheGenerated304ForValidatorShouldNotContainEntityHeader(headerName,
                 headerValue, "Last-Modified", DateUtils.formatDate(twoMinutesAgo),
                 "If-Modified-Since");
     }
 
     @Test
     public void cacheGenerated304ForStrongEtagValidatorShouldNotContainAllow() throws Exception {
         cacheGenerated304ForStrongETagValidatorShouldNotContainEntityHeader(
                 "Allow", "GET,HEAD");
     }
 
     @Test
     public void cacheGenerated304ForStrongDateValidatorShouldNotContainAllow() throws Exception {
         cacheGenerated304ForStrongDateValidatorShouldNotContainEntityHeader(
                 "Allow", "GET,HEAD");
     }
 
     @Test
     public void cacheGenerated304ForStrongEtagValidatorShouldNotContainContentEncoding() throws Exception {
         cacheGenerated304ForStrongETagValidatorShouldNotContainEntityHeader(
                 "Content-Encoding", "gzip");
     }
 
     @Test
     public void cacheGenerated304ForStrongDateValidatorShouldNotContainContentEncoding() throws Exception {
         cacheGenerated304ForStrongDateValidatorShouldNotContainEntityHeader(
                 "Content-Encoding", "gzip");
     }
 
     @Test
     public void cacheGenerated304ForStrongEtagValidatorShouldNotContainContentLanguage() throws Exception {
         cacheGenerated304ForStrongETagValidatorShouldNotContainEntityHeader(
                 "Content-Language", "en");
     }
 
     @Test
     public void cacheGenerated304ForStrongDateValidatorShouldNotContainContentLanguage() throws Exception {
         cacheGenerated304ForStrongDateValidatorShouldNotContainEntityHeader(
                 "Content-Language", "en");
     }
 
     @Test
     public void cacheGenerated304ForStrongValidatorShouldNotContainContentLength() throws Exception {
         cacheGenerated304ForStrongETagValidatorShouldNotContainEntityHeader(
                 "Content-Length", "128");
     }
 
     @Test
     public void cacheGenerated304ForStrongDateValidatorShouldNotContainContentLength() throws Exception {
         cacheGenerated304ForStrongDateValidatorShouldNotContainEntityHeader(
                 "Content-Length", "128");
     }
 
     @Test
     public void cacheGenerated304ForStrongValidatorShouldNotContainContentMD5() throws Exception {
         cacheGenerated304ForStrongETagValidatorShouldNotContainEntityHeader(
                 "Content-MD5", "Q2hlY2sgSW50ZWdyaXR5IQ==");
     }
 
     @Test
     public void cacheGenerated304ForStrongDateValidatorShouldNotContainContentMD5() throws Exception {
         cacheGenerated304ForStrongDateValidatorShouldNotContainEntityHeader(
                 "Content-MD5", "Q2hlY2sgSW50ZWdyaXR5IQ==");
     }
 
     private void cacheGenerated304ForStrongValidatorShouldNotContainContentRange(
             final String validatorHeader, final String validator, final String conditionalHeader) throws Exception {
         final ClassicHttpRequest req1 = HttpTestUtils.makeDefaultRequest();
         req1.setHeader("Range","bytes=0-127");
         final ClassicHttpResponse resp1 = new BasicClassicHttpResponse(HttpStatus.SC_PARTIAL_CONTENT, "Partial Content");
         resp1.setHeader("Cache-Control","max-age=3600");
         resp1.setHeader(validatorHeader, validator);
         resp1.setHeader("Content-Range", "bytes 0-127/256");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = HttpTestUtils.makeDefaultRequest();
         req2.setHeader("If-Range", validator);
         req2.setHeader("Range","bytes=0-127");
         req2.setHeader(conditionalHeader, validator);
 
         final ClassicHttpResponse resp2 = new BasicClassicHttpResponse(HttpStatus.SC_NOT_MODIFIED, "Not Modified");
         resp2.setHeader("Date", DateUtils.formatDate(now));
         resp2.setHeader(validatorHeader, validator);
 
         // cache module does not currently deal with byte ranges, but we want
         // this test to work even if it does some day
         final Capture<ClassicHttpRequest> cap = EasyMock.newCapture();
         EasyMock.expect(
                 mockExecChain.proceed(
                         EasyMock.capture(cap),
                         EasyMock.isA(ExecChain.Scope.class))).andReturn(resp2).times(0,1);
 
         replayMocks();
         execute(req1);
         final ClassicHttpResponse result = execute(req2);
         verifyMocks();
 
         if (!cap.hasCaptured()
             && HttpStatus.SC_NOT_MODIFIED == result.getCode()) {
             // cache generated a 304
             assertNull(result.getFirstHeader("Content-Range"));
         }
     }
 
     @Test
     public void cacheGenerated304ForStrongEtagValidatorShouldNotContainContentRange() throws Exception {
         cacheGenerated304ForStrongValidatorShouldNotContainContentRange(
                 "ETag", "\"etag\"", "If-None-Match");
     }
 
     @Test
     public void cacheGenerated304ForStrongDateValidatorShouldNotContainContentRange() throws Exception {
         cacheGenerated304ForStrongValidatorShouldNotContainContentRange(
                 "Last-Modified", DateUtils.formatDate(twoMinutesAgo), "If-Modified-Since");
     }
 
     @Test
     public void cacheGenerated304ForStrongEtagValidatorShouldNotContainContentType() throws Exception {
         cacheGenerated304ForStrongETagValidatorShouldNotContainEntityHeader(
                 "Content-Type", "text/html");
     }
 
     @Test
     public void cacheGenerated304ForStrongDateValidatorShouldNotContainContentType() throws Exception {
         cacheGenerated304ForStrongDateValidatorShouldNotContainEntityHeader(
                 "Content-Type", "text/html");
     }
 
     @Test
     public void cacheGenerated304ForStrongEtagValidatorShouldNotContainLastModified() throws Exception {
         cacheGenerated304ForStrongETagValidatorShouldNotContainEntityHeader(
                 "Last-Modified", DateUtils.formatDate(tenSecondsAgo));
     }
 
     @Test
     public void cacheGenerated304ForStrongDateValidatorShouldNotContainLastModified() throws Exception {
         cacheGenerated304ForStrongDateValidatorShouldNotContainEntityHeader(
                 "Last-Modified", DateUtils.formatDate(twoMinutesAgo));
     }
 
     private void shouldStripEntityHeaderFromOrigin304ResponseToStrongValidation(
             final String entityHeader, final String entityHeaderValue) throws Exception {
         final ClassicHttpRequest req = HttpTestUtils.makeDefaultRequest();
         req.setHeader("If-None-Match", "\"etag\"");
 
         final ClassicHttpResponse resp = new BasicClassicHttpResponse(HttpStatus.SC_NOT_MODIFIED, "Not Modified");
         resp.setHeader("Date", DateUtils.formatDate(now));
         resp.setHeader("Etag", "\"etag\"");
         resp.setHeader(entityHeader, entityHeaderValue);
 
         backendExpectsAnyRequestAndReturn(resp);
 
         replayMocks();
         final ClassicHttpResponse result = execute(req);
         verifyMocks();
 
         assertNull(result.getFirstHeader(entityHeader));
     }
 
     @Test
     public void shouldStripAllowFromOrigin304ResponseToStrongValidation() throws Exception {
         shouldStripEntityHeaderFromOrigin304ResponseToStrongValidation(
                 "Allow", "GET,HEAD");
     }
 
     @Test
     public void shouldStripContentEncodingFromOrigin304ResponseToStrongValidation() throws Exception {
         shouldStripEntityHeaderFromOrigin304ResponseToStrongValidation(
                 "Content-Encoding", "gzip");
     }
 
     @Test
     public void shouldStripContentLanguageFromOrigin304ResponseToStrongValidation() throws Exception {
         shouldStripEntityHeaderFromOrigin304ResponseToStrongValidation(
                 "Content-Language", "en");
     }
 
     @Test
     public void shouldStripContentLengthFromOrigin304ResponseToStrongValidation() throws Exception {
         shouldStripEntityHeaderFromOrigin304ResponseToStrongValidation(
                 "Content-Length", "128");
     }
 
     @Test
     public void shouldStripContentMD5FromOrigin304ResponseToStrongValidation() throws Exception {
         shouldStripEntityHeaderFromOrigin304ResponseToStrongValidation(
                 "Content-MD5", "Q2hlY2sgSW50ZWdyaXR5IQ==");
     }
 
     @Test
     public void shouldStripContentTypeFromOrigin304ResponseToStrongValidation() throws Exception {
         shouldStripEntityHeaderFromOrigin304ResponseToStrongValidation(
                 "Content-Type", "text/html;charset=utf-8");
     }
 
     @Test
     public void shouldStripContentRangeFromOrigin304ResponseToStringValidation() throws Exception {
         final ClassicHttpRequest req = HttpTestUtils.makeDefaultRequest();
         req.setHeader("If-Range","\"etag\"");
         req.setHeader("Range","bytes=0-127");
 
         final ClassicHttpResponse resp = new BasicClassicHttpResponse(HttpStatus.SC_NOT_MODIFIED, "Not Modified");
         resp.setHeader("Date", DateUtils.formatDate(now));
         resp.setHeader("ETag", "\"etag\"");
         resp.setHeader("Content-Range", "bytes 0-127/256");
 
         backendExpectsAnyRequestAndReturn(resp);
 
         replayMocks();
         final ClassicHttpResponse result = execute(req);
         verifyMocks();
 
         assertNull(result.getFirstHeader("Content-Range"));
     }
 
     @Test
     public void shouldStripLastModifiedFromOrigin304ResponseToStrongValidation() throws Exception {
         shouldStripEntityHeaderFromOrigin304ResponseToStrongValidation(
                 "Last-Modified", DateUtils.formatDate(twoMinutesAgo));
     }
 
     /*
      * "For this reason, a cache SHOULD NOT return a stale response if the
      * client explicitly requests a first-hand or fresh one, unless it is
      * impossible to comply for technical or policy reasons."
      */
     private ClassicHttpRequest requestToPopulateStaleCacheEntry() throws Exception {
         final ClassicHttpRequest req1 = new BasicClassicHttpRequest("GET", "/");
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         resp1.setHeader("Cache-Control","public,max-age=5");
         resp1.setHeader("Etag","\"etag\"");
 
         backendExpectsAnyRequestAndReturn(resp1);
         return req1;
     }
 
     private void testDoesNotReturnStaleResponseOnError(final ClassicHttpRequest req2) throws Exception {
         final ClassicHttpRequest req1 = requestToPopulateStaleCacheEntry();
 
         backendExpectsAnyRequest().andThrow(new IOException());
 
         replayMocks();
         execute(req1);
         ClassicHttpResponse result = null;
         try {
             result = execute(req2);
         } catch (final IOException acceptable) {
         }
         verifyMocks();
 
         if (result != null) {
             assertFalse(result.getCode() == HttpStatus.SC_OK);
         }
     }
 
     @Test
     public void testDoesNotReturnStaleResponseIfClientExplicitlyRequestsFirstHandOneWithCacheControl() throws Exception {
         final ClassicHttpRequest req = new BasicClassicHttpRequest("GET", "/");
         req.setHeader("Cache-Control","no-cache");
         testDoesNotReturnStaleResponseOnError(req);
     }
 
     @Test
     public void testDoesNotReturnStaleResponseIfClientExplicitlyRequestsFirstHandOneWithPragma() throws Exception {
         final ClassicHttpRequest req = new BasicClassicHttpRequest("GET", "/");
         req.setHeader("Pragma","no-cache");
         testDoesNotReturnStaleResponseOnError(req);
     }
 
     @Test
     public void testDoesNotReturnStaleResponseIfClientExplicitlyRequestsFreshWithMaxAge() throws Exception {
         final ClassicHttpRequest req = new BasicClassicHttpRequest("GET", "/");
         req.setHeader("Cache-Control","max-age=0");
         testDoesNotReturnStaleResponseOnError(req);
     }
 
     @Test
     public void testDoesNotReturnStaleResponseIfClientExplicitlySpecifiesLargerMaxAge() throws Exception {
         final ClassicHttpRequest req = new BasicClassicHttpRequest("GET", "/");
         req.setHeader("Cache-Control","max-age=20");
         testDoesNotReturnStaleResponseOnError(req);
     }
 
 
     @Test
     public void testDoesNotReturnStaleResponseIfClientExplicitlyRequestsFreshWithMinFresh() throws Exception {
         final ClassicHttpRequest req = new BasicClassicHttpRequest("GET", "/");
         req.setHeader("Cache-Control","min-fresh=2");
 
         testDoesNotReturnStaleResponseOnError(req);
     }
 
     @Test
     public void testDoesNotReturnStaleResponseIfClientExplicitlyRequestsFreshWithMaxStale() throws Exception {
         final ClassicHttpRequest req = new BasicClassicHttpRequest("GET", "/");
         req.setHeader("Cache-Control","max-stale=2");
 
         testDoesNotReturnStaleResponseOnError(req);
     }
 
     @Test
     public void testMayReturnStaleResponseIfClientExplicitlySpecifiesAcceptableMaxStale() throws Exception {
         final ClassicHttpRequest req1 = requestToPopulateStaleCacheEntry();
         final ClassicHttpRequest req2 = new BasicClassicHttpRequest("GET", "/");
         req2.setHeader("Cache-Control","max-stale=20");
 
         backendExpectsAnyRequest().andThrow(new IOException()).times(0,1);
 
         replayMocks();
         execute(req1);
         final ClassicHttpResponse result = execute(req2);
         verifyMocks();
 
         assertEquals(HttpStatus.SC_OK, result.getCode());
         assertNotNull(result.getFirstHeader("Warning"));
     }
 
     /*
      * "A correct cache MUST respond to a request with the most up-to-date
      * response held by the cache that is appropriate to the request
      * (see sections 13.2.5, 13.2.6, and 13.12) which meets one of the
      * following conditions:
      *
      * 1. It has been checked for equivalence with what the origin server
      * would have returned by revalidating the response with the
      * origin server (section 13.3);
      *
      * 2. It is "fresh enough" (see section 13.2). In the default case,
      * this means it meets the least restrictive freshness requirement
      * of the client, origin server, and cache (see section 14.9); if
      * the origin server so specifies, it is the freshness requirement
      * of the origin server alone.
      *
      * If a stored response is not "fresh enough" by the most
      * restrictive freshness requirement of both the client and the
      * origin server, in carefully considered circumstances the cache
      * MAY still return the response with the appropriate Warning
      * header (see section 13.1.5 and 14.46), unless such a response
      * is prohibited (e.g., by a "no-store" cache-directive, or by a
      * "no-cache" cache-request-directive; see section 14.9).
      *
      * 3. It is an appropriate 304 (Not Modified), 305 (Proxy Redirect),
      * or error (4xx or 5xx) response message.
      *
      * If the cache can not communicate with the origin server, then a
      * correct cache SHOULD respond as above if the response can be
      * correctly served from the cache..."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.1.1
      */
     @Test
     public void testReturnsCachedResponsesAppropriatelyWhenNoOriginCommunication() throws Exception {
         final ClassicHttpRequest req1 = new BasicClassicHttpRequest("GET", "/");
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Cache-Control", "public, max-age=5");
         resp1.setHeader("ETag","\"etag\"");
         resp1.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = new BasicClassicHttpRequest("GET", "/");
 
         backendExpectsAnyRequest().andThrow(new IOException()).anyTimes();
 
         replayMocks();
         execute(req1);
         final ClassicHttpResponse result = execute(req2);
         verifyMocks();
 
         assertEquals(HttpStatus.SC_OK, result.getCode());
         boolean warning111Found = false;
         for(final Header h : result.getHeaders("Warning")) {
             for(final WarningValue wv : WarningValue.getWarningValues(h)) {
                 if (wv.getWarnCode() == 111) {
                     warning111Found = true;
                     break;
                 }
             }
         }
         assertTrue(warning111Found);
     }
 
     /*
      * "If a cache receives a response (either an entire response, or a
      * 304 (Not Modified) response) that it would normally forward to the
      * requesting client, and the received response is no longer fresh,
      * the cache SHOULD forward it to the requesting client without adding
      * a new Warning (but without removing any existing Warning headers).
      * A cache SHOULD NOT attempt to revalidate a response simply because
      * that response became stale in transit; this might lead to an
      * infinite loop."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.1.1
      */
     @Test
     public void testDoesNotAddNewWarningHeaderIfResponseArrivesStale() throws Exception {
         originResponse.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         originResponse.setHeader("Cache-Control","public, max-age=5");
         originResponse.setHeader("ETag","\"etag\"");
 
         backendExpectsAnyRequest().andReturn(originResponse);
 
         replayMocks();
         final ClassicHttpResponse result = execute(request);
         verifyMocks();
 
         assertNull(result.getFirstHeader("Warning"));
     }
 
     @Test
     public void testForwardsExistingWarningHeadersOnResponseThatArrivesStale() throws Exception {
         originResponse.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         originResponse.setHeader("Cache-Control","public, max-age=5");
         originResponse.setHeader("ETag","\"etag\"");
         originResponse.addHeader("Age","10");
         final String warning = "110 fred \"Response is stale\"";
         originResponse.addHeader("Warning",warning);
 
         backendExpectsAnyRequest().andReturn(originResponse);
 
         replayMocks();
         final ClassicHttpResponse result = execute(request);
         verifyMocks();
 
         assertEquals(warning, result.getFirstHeader("Warning").getValue());
     }
 
     /*
      * "A transparent proxy SHOULD NOT modify an end-to-end header unless
      * the definition of that header requires or specifically allows that."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.5.2
      */
     private void testDoesNotModifyHeaderOnResponses(final String headerName) throws Exception {
         final String headerValue = HttpTestUtils
             .getCanonicalHeaderValue(originResponse, headerName);
         backendExpectsAnyRequest().andReturn(originResponse);
         replayMocks();
         final ClassicHttpResponse result = execute(request);
         verifyMocks();
         assertEquals(headerValue,
             result.getFirstHeader(headerName).getValue());
     }
 
     private void testDoesNotModifyHeaderOnRequests(final String headerName) throws Exception {
         final String headerValue = HttpTestUtils.getCanonicalHeaderValue(request, headerName);
         final Capture<ClassicHttpRequest> cap = EasyMock.newCapture();
         EasyMock.expect(
                 mockExecChain.proceed(
                         EasyMock.capture(cap),
                         EasyMock.isA(ExecChain.Scope.class))).andReturn(originResponse);
         replayMocks();
         execute(request);
         verifyMocks();
         assertEquals(headerValue,
                 HttpTestUtils.getCanonicalHeaderValue(cap.getValue(),
                         headerName));
     }
 
     @Test
     public void testDoesNotModifyAcceptRangesOnResponses() throws Exception {
         final String headerName = "Accept-Ranges";
         originResponse.setHeader(headerName,"bytes");
         testDoesNotModifyHeaderOnResponses(headerName);
     }
 
     @Test
     public void testDoesNotModifyAuthorizationOnRequests() throws Exception {
         request.setHeader("Authorization", StandardAuthScheme.BASIC + " dXNlcjpwYXNzd2Q=");
         testDoesNotModifyHeaderOnRequests("Authorization");
     }
 
     @Test
     public void testDoesNotModifyContentLengthOnRequests() throws Exception {
         final ClassicHttpRequest post = new BasicClassicHttpRequest("POST", "/");
         post.setEntity(HttpTestUtils.makeBody(128));
         post.setHeader("Content-Length","128");
         request = post;
         testDoesNotModifyHeaderOnRequests("Content-Length");
     }
 
     @Test
     public void testDoesNotModifyContentLengthOnResponses() throws Exception {
         originResponse.setEntity(HttpTestUtils.makeBody(128));
         originResponse.setHeader("Content-Length","128");
         testDoesNotModifyHeaderOnResponses("Content-Length");
     }
 
     @Test
     public void testDoesNotModifyContentMD5OnRequests() throws Exception {
         final ClassicHttpRequest post = new BasicClassicHttpRequest("POST", "/");
         post.setEntity(HttpTestUtils.makeBody(128));
         post.setHeader("Content-Length","128");
         post.setHeader("Content-MD5","Q2hlY2sgSW50ZWdyaXR5IQ==");
         request = post;
         testDoesNotModifyHeaderOnRequests("Content-MD5");
     }
 
     @Test
     public void testDoesNotModifyContentMD5OnResponses() throws Exception {
         originResponse.setEntity(HttpTestUtils.makeBody(128));
         originResponse.setHeader("Content-MD5","Q2hlY2sgSW50ZWdyaXR5IQ==");
         testDoesNotModifyHeaderOnResponses("Content-MD5");
     }
 
     @Test
     public void testDoesNotModifyContentRangeOnRequests() throws Exception {
         final ClassicHttpRequest put = new BasicClassicHttpRequest("PUT", "/");
         put.setEntity(HttpTestUtils.makeBody(128));
         put.setHeader("Content-Length","128");
         put.setHeader("Content-Range","bytes 0-127/256");
         request = put;
         testDoesNotModifyHeaderOnRequests("Content-Range");
     }
 
     @Test
     public void testDoesNotModifyContentRangeOnResponses() throws Exception {
         request.setHeader("Range","bytes=0-128");
         originResponse.setCode(HttpStatus.SC_PARTIAL_CONTENT);
         originResponse.setReasonPhrase("Partial Content");
         originResponse.setEntity(HttpTestUtils.makeBody(128));
         originResponse.setHeader("Content-Range","bytes 0-127/256");
         testDoesNotModifyHeaderOnResponses("Content-Range");
     }
 
     @Test
     public void testDoesNotModifyContentTypeOnRequests() throws Exception {
         final ClassicHttpRequest post = new BasicClassicHttpRequest("POST", "/");
         post.setEntity(HttpTestUtils.makeBody(128));
         post.setHeader("Content-Length","128");
         post.setHeader("Content-Type","application/octet-stream");
         request = post;
         testDoesNotModifyHeaderOnRequests("Content-Type");
     }
 
     @Test
     public void testDoesNotModifyContentTypeOnResponses() throws Exception {
         originResponse.setHeader("Content-Type","application/octet-stream");
         testDoesNotModifyHeaderOnResponses("Content-Type");
     }
 
     @Test
     public void testDoesNotModifyDateOnRequests() throws Exception {
         request.setHeader("Date", DateUtils.formatDate(new Date()));
         testDoesNotModifyHeaderOnRequests("Date");
     }
 
     @Test
     public void testDoesNotModifyDateOnResponses() throws Exception {
         originResponse.setHeader("Date", DateUtils.formatDate(new Date()));
         testDoesNotModifyHeaderOnResponses("Date");
     }
 
     @Test
     public void testDoesNotModifyETagOnResponses() throws Exception {
         originResponse.setHeader("ETag", "\"random-etag\"");
         testDoesNotModifyHeaderOnResponses("ETag");
     }
 
     @Test
     public void testDoesNotModifyExpiresOnResponses() throws Exception {
         originResponse.setHeader("Expires", DateUtils.formatDate(new Date()));
         testDoesNotModifyHeaderOnResponses("Expires");
     }
 
     @Test
     public void testDoesNotModifyFromOnRequests() throws Exception {
         request.setHeader("From", "foo@example.com");
         testDoesNotModifyHeaderOnRequests("From");
     }
 
     @Test
     public void testDoesNotModifyIfMatchOnRequests() throws Exception {
         request = new BasicClassicHttpRequest("DELETE", "/");
         request.setHeader("If-Match", "\"etag\"");
         testDoesNotModifyHeaderOnRequests("If-Match");
     }
 
     @Test
     public void testDoesNotModifyIfModifiedSinceOnRequests() throws Exception {
         request.setHeader("If-Modified-Since", DateUtils.formatDate(new Date()));
         testDoesNotModifyHeaderOnRequests("If-Modified-Since");
     }
 
     @Test
     public void testDoesNotModifyIfNoneMatchOnRequests() throws Exception {
         request.setHeader("If-None-Match", "\"etag\"");
         testDoesNotModifyHeaderOnRequests("If-None-Match");
     }
 
     @Test
     public void testDoesNotModifyIfRangeOnRequests() throws Exception {
         request.setHeader("Range","bytes=0-128");
         request.setHeader("If-Range", "\"etag\"");
         testDoesNotModifyHeaderOnRequests("If-Range");
     }
 
     @Test
     public void testDoesNotModifyIfUnmodifiedSinceOnRequests() throws Exception {
         request = new BasicClassicHttpRequest("DELETE", "/");
         request.setHeader("If-Unmodified-Since", DateUtils.formatDate(new Date()));
         testDoesNotModifyHeaderOnRequests("If-Unmodified-Since");
     }
 
     @Test
     public void testDoesNotModifyLastModifiedOnResponses() throws Exception {
         originResponse.setHeader("Last-Modified", DateUtils.formatDate(new Date()));
         testDoesNotModifyHeaderOnResponses("Last-Modified");
     }
 
     @Test
     public void testDoesNotModifyLocationOnResponses() throws Exception {
         originResponse.setCode(HttpStatus.SC_TEMPORARY_REDIRECT);
         originResponse.setReasonPhrase("Temporary Redirect");
         originResponse.setHeader("Location", "http://foo.example.com/bar");
         testDoesNotModifyHeaderOnResponses("Location");
     }
 
     @Test
     public void testDoesNotModifyRangeOnRequests() throws Exception {
         request.setHeader("Range", "bytes=0-128");
         testDoesNotModifyHeaderOnRequests("Range");
     }
 
     @Test
     public void testDoesNotModifyRefererOnRequests() throws Exception {
         request.setHeader("Referer", "http://foo.example.com/bar");
         testDoesNotModifyHeaderOnRequests("Referer");
     }
 
     @Test
     public void testDoesNotModifyRetryAfterOnResponses() throws Exception {
         originResponse.setCode(HttpStatus.SC_SERVICE_UNAVAILABLE);
         originResponse.setReasonPhrase("Service Unavailable");
         originResponse.setHeader("Retry-After", "120");
         testDoesNotModifyHeaderOnResponses("Retry-After");
     }
 
     @Test
     public void testDoesNotModifyServerOnResponses() throws Exception {
         originResponse.setHeader("Server", "SomeServer/1.0");
         testDoesNotModifyHeaderOnResponses("Server");
     }
 
     @Test
     public void testDoesNotModifyUserAgentOnRequests() throws Exception {
         request.setHeader("User-Agent", "MyClient/1.0");
         testDoesNotModifyHeaderOnRequests("User-Agent");
     }
 
     @Test
     public void testDoesNotModifyVaryOnResponses() throws Exception {
         request.setHeader("Accept-Encoding","identity");
         originResponse.setHeader("Vary", "Accept-Encoding");
         testDoesNotModifyHeaderOnResponses("Vary");
     }
 
     @Test
     public void testDoesNotModifyExtensionHeaderOnRequests() throws Exception {
         request.setHeader("X-Extension","x-value");
         testDoesNotModifyHeaderOnRequests("X-Extension");
     }
 
     @Test
     public void testDoesNotModifyExtensionHeaderOnResponses() throws Exception {
         originResponse.setHeader("X-Extension", "x-value");
         testDoesNotModifyHeaderOnResponses("X-Extension");
     }
 
 
     /*
      * "[HTTP/1.1 clients], If only a Last-Modified value has been provided
      * by the origin server, SHOULD use that value in non-subrange cache-
      * conditional requests (using If-Modified-Since)."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.3.4
      */
     @Test
     public void testUsesLastModifiedDateForCacheConditionalRequests() throws Exception {
         final Date twentySecondsAgo = new Date(now.getTime() - 20 * 1000L);
         final String lmDate = DateUtils.formatDate(twentySecondsAgo);
 
         final ClassicHttpRequest req1 =
             new BasicClassicHttpRequest("GET", "/");
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         resp1.setHeader("Last-Modified", lmDate);
         resp1.setHeader("Cache-Control","max-age=5");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final Capture<ClassicHttpRequest> cap = EasyMock.newCapture();
         final ClassicHttpRequest req2 = new BasicClassicHttpRequest("GET", "/");
         final ClassicHttpResponse resp2 = HttpTestUtils.make200Response();
 
         EasyMock.expect(
                 mockExecChain.proceed(
                         EasyMock.capture(cap),
                         EasyMock.isA(ExecChain.Scope.class))).andReturn(resp2);
 
         replayMocks();
         execute(req1);
         execute(req2);
         verifyMocks();
 
         final ClassicHttpRequest captured = cap.getValue();
         final Header ifModifiedSince =
             captured.getFirstHeader("If-Modified-Since");
         assertEquals(lmDate, ifModifiedSince.getValue());
     }
 
     /*
      * "[HTTP/1.1 clients], if both an entity tag and a Last-Modified value
      * have been provided by the origin server, SHOULD use both validators
      * in cache-conditional requests. This allows both HTTP/1.0 and
      * HTTP/1.1 caches to respond appropriately."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.3.4
      */
     @Test
     public void testUsesBothLastModifiedAndETagForConditionalRequestsIfAvailable() throws Exception {
         final Date twentySecondsAgo = new Date(now.getTime() - 20 * 1000L);
         final String lmDate = DateUtils.formatDate(twentySecondsAgo);
         final String etag = "\"etag\"";
 
         final ClassicHttpRequest req1 = new BasicClassicHttpRequest("GET", "/");
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         resp1.setHeader("Last-Modified", lmDate);
         resp1.setHeader("Cache-Control","max-age=5");
         resp1.setHeader("ETag", etag);
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final Capture<ClassicHttpRequest> cap = EasyMock.newCapture();
         final ClassicHttpRequest req2 = new BasicClassicHttpRequest("GET", "/");
         final ClassicHttpResponse resp2 = HttpTestUtils.make200Response();
 
         EasyMock.expect(
                 mockExecChain.proceed(
                         EasyMock.capture(cap),
                         EasyMock.isA(ExecChain.Scope.class))).andReturn(resp2);
 
         replayMocks();
         execute(req1);
         execute(req2);
         verifyMocks();
 
         final ClassicHttpRequest captured = cap.getValue();
         final Header ifModifiedSince =
             captured.getFirstHeader("If-Modified-Since");
         assertEquals(lmDate, ifModifiedSince.getValue());
         final Header ifNoneMatch =
             captured.getFirstHeader("If-None-Match");
         assertEquals(etag, ifNoneMatch.getValue());
     }
 
     /*
      * "If an origin server wishes to force a semantically transparent cache
      * to validate every request, it MAY assign an explicit expiration time
      * in the past. This means that the response is always stale, and so the
      * cache SHOULD validate it before using it for subsequent requests."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.2.1
      */
     @Test
     public void testRevalidatesCachedResponseWithExpirationInThePast() throws Exception {
         final Date oneSecondAgo = new Date(now.getTime() - 1 * 1000L);
         final Date oneSecondFromNow = new Date(now.getTime() + 1 * 1000L);
         final Date twoSecondsFromNow = new Date(now.getTime() + 2 * 1000L);
         final ClassicHttpRequest req1 = new BasicClassicHttpRequest("GET", "/");
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("ETag","\"etag\"");
         resp1.setHeader("Date", DateUtils.formatDate(now));
         resp1.setHeader("Expires",DateUtils.formatDate(oneSecondAgo));
         resp1.setHeader("Cache-Control", "public");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = new BasicClassicHttpRequest("GET", "/");
         final ClassicHttpRequest revalidate = new BasicClassicHttpRequest("GET", "/");
         revalidate.setHeader("If-None-Match","\"etag\"");
 
         final ClassicHttpResponse resp2 = HttpTestUtils.make304Response();
         resp2.setHeader("Date", DateUtils.formatDate(twoSecondsFromNow));
         resp2.setHeader("Expires", DateUtils.formatDate(oneSecondFromNow));
         resp2.setHeader("ETag","\"etag\"");
 
         EasyMock.expect(
                 mockExecChain.proceed(
                         eqRequest(revalidate),
                         EasyMock.isA(ExecChain.Scope.class))).andReturn(resp2);
 
         replayMocks();
         execute(req1);
         final ClassicHttpResponse result = execute(req2);
         verifyMocks();
 
         assertEquals(HttpStatus.SC_OK,
                 result.getCode());
     }
 
     /* "When a client tries to revalidate a cache entry, and the response
      * it receives contains a Date header that appears to be older than the
      * one for the existing entry, then the client SHOULD repeat the
      * request unconditionally, and include
      *     Cache-Control: max-age=0
      * to force any intermediate caches to validate their copies directly
      * with the origin server, or
      *     Cache-Control: no-cache
      * to force any intermediate caches to obtain a new copy from the
      * origin server."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.2.6
      */
     @Test
     public void testRetriesValidationThatResultsInAnOlderDated304Response() throws Exception {
         final Date elevenSecondsAgo = new Date(now.getTime() - 11 * 1000L);
         final ClassicHttpRequest req1 = new BasicClassicHttpRequest("GET", "/");
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("ETag","\"etag\"");
         resp1.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         resp1.setHeader("Cache-Control","max-age=5");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = new BasicClassicHttpRequest("GET", "/");
         final ClassicHttpResponse resp2 = HttpTestUtils.make304Response();
         resp2.setHeader("ETag","\"etag\"");
         resp2.setHeader("Date", DateUtils.formatDate(elevenSecondsAgo));
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         final Capture<ClassicHttpRequest> cap = EasyMock.newCapture();
         final ClassicHttpResponse resp3 = HttpTestUtils.make200Response();
         resp3.setHeader("ETag","\"etag2\"");
         resp3.setHeader("Date", DateUtils.formatDate(now));
         resp3.setHeader("Cache-Control","max-age=5");
 
         EasyMock.expect(
                 mockExecChain.proceed(
                         EasyMock.capture(cap),
                         EasyMock.isA(ExecChain.Scope.class))).andReturn(resp3);
 
         replayMocks();
         execute(req1);
         execute(req2);
         verifyMocks();
 
         final ClassicHttpRequest captured = cap.getValue();
         boolean hasMaxAge0 = false;
         boolean hasNoCache = false;
         final Iterator<HeaderElement> it = MessageSupport.iterate(captured, HttpHeaders.CACHE_CONTROL);
         while (it.hasNext()) {
             final HeaderElement elt = it.next();
             if ("max-age".equals(elt.getName())) {
                 try {
                     final int maxage = Integer.parseInt(elt.getValue());
                     if (maxage == 0) {
                         hasMaxAge0 = true;
                     }
                 } catch (final NumberFormatException nfe) {
                     // nop
                 }
             } else if ("no-cache".equals(elt.getName())) {
                 hasNoCache = true;
             }
         }
         assertTrue(hasMaxAge0 || hasNoCache);
         assertNull(captured.getFirstHeader("If-None-Match"));
         assertNull(captured.getFirstHeader("If-Modified-Since"));
         assertNull(captured.getFirstHeader("If-Range"));
         assertNull(captured.getFirstHeader("If-Match"));
         assertNull(captured.getFirstHeader("If-Unmodified-Since"));
     }
 
     /* "If an entity tag was assigned to a cached representation, the
      * forwarded request SHOULD be conditional and include the entity
      * tags in an If-None-Match header field from all its cache entries
      * for the resource."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.6
      */
     @Test
     public void testSendsAllVariantEtagsInConditionalRequest() throws Exception {
         final ClassicHttpRequest req1 = new BasicClassicHttpRequest("GET","/");
         req1.setHeader("User-Agent","agent1");
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Cache-Control","max-age=3600");
         resp1.setHeader("Vary","User-Agent");
         resp1.setHeader("Etag","\"etag1\"");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = new BasicClassicHttpRequest("GET","/");
         req2.setHeader("User-Agent","agent2");
         final ClassicHttpResponse resp2 = HttpTestUtils.make200Response();
         resp2.setHeader("Cache-Control","max-age=3600");
         resp2.setHeader("Vary","User-Agent");
         resp2.setHeader("Etag","\"etag2\"");
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         final Capture<ClassicHttpRequest> cap = EasyMock.newCapture();
         final ClassicHttpRequest req3 = new BasicClassicHttpRequest("GET","/");
         req3.setHeader("User-Agent","agent3");
         final ClassicHttpResponse resp3 = HttpTestUtils.make200Response();
 
         EasyMock.expect(
                 mockExecChain.proceed(
                         EasyMock.capture(cap),
                         EasyMock.isA(ExecChain.Scope.class))).andReturn(resp3);
 
         replayMocks();
         execute(req1);
         execute(req2);
         execute(req3);
         verifyMocks();
 
         final ClassicHttpRequest captured = cap.getValue();
         boolean foundEtag1 = false;
         boolean foundEtag2 = false;
         for(final Header h : captured.getHeaders("If-None-Match")) {
             for(final String etag : h.getValue().split(",")) {
                 if ("\"etag1\"".equals(etag.trim())) {
                     foundEtag1 = true;
                 }
                 if ("\"etag2\"".equals(etag.trim())) {
                     foundEtag2 = true;
                 }
             }
         }
         assertTrue(foundEtag1 && foundEtag2);
     }
 
     /* "If the entity-tag of the new response matches that of an existing
      * entry, the new response SHOULD be used to processChallenge the header fields
      * of the existing entry, and the result MUST be returned to the
      * client."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.6
      */
     @Test
     public void testResponseToExistingVariantsUpdatesEntry() throws Exception {
 
         final ClassicHttpRequest req1 = new BasicClassicHttpRequest("GET", "/");
         req1.setHeader("User-Agent", "agent1");
 
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         resp1.setHeader("Vary", "User-Agent");
         resp1.setHeader("Cache-Control", "max-age=3600");
         resp1.setHeader("ETag", "\"etag1\"");
 
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = new BasicClassicHttpRequest("GET", "/");
         req2.setHeader("User-Agent", "agent2");
 
         final ClassicHttpResponse resp2 = HttpTestUtils.make200Response();
         resp2.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         resp2.setHeader("Vary", "User-Agent");
         resp2.setHeader("Cache-Control", "max-age=3600");
         resp2.setHeader("ETag", "\"etag2\"");
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         final ClassicHttpRequest req3 = new BasicClassicHttpRequest("GET", "/");
         req3.setHeader("User-Agent", "agent3");
 
         final ClassicHttpResponse resp3 = new BasicClassicHttpResponse(HttpStatus.SC_NOT_MODIFIED, "Not Modified");
         resp3.setHeader("Date", DateUtils.formatDate(now));
         resp3.setHeader("ETag", "\"etag1\"");
 
         backendExpectsAnyRequestAndReturn(resp3);
 
         final ClassicHttpRequest req4 = new BasicClassicHttpRequest("GET", "/");
         req4.setHeader("User-Agent", "agent1");
 
         replayMocks();
         execute(req1);
         execute(req2);
         final ClassicHttpResponse result1 = execute(req3);
         final ClassicHttpResponse result2 = execute(req4);
         verifyMocks();
 
         assertEquals(HttpStatus.SC_OK, result1.getCode());
         assertEquals("\"etag1\"", result1.getFirstHeader("ETag").getValue());
         assertEquals(DateUtils.formatDate(now), result1.getFirstHeader("Date").getValue());
         assertEquals(DateUtils.formatDate(now), result2.getFirstHeader("Date").getValue());
     }
 
     @Test
     public void testResponseToExistingVariantsIsCachedForFutureResponses() throws Exception {
 
         final ClassicHttpRequest req1 = new BasicClassicHttpRequest("GET", "/");
         req1.setHeader("User-Agent", "agent1");
 
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         resp1.setHeader("Vary", "User-Agent");
         resp1.setHeader("Cache-Control", "max-age=3600");
         resp1.setHeader("ETag", "\"etag1\"");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = new BasicClassicHttpRequest("GET", "/");
         req2.setHeader("User-Agent", "agent2");
 
         final ClassicHttpResponse resp2 = new BasicClassicHttpResponse(HttpStatus.SC_NOT_MODIFIED, "Not Modified");
         resp2.setHeader("Date", DateUtils.formatDate(now));
         resp2.setHeader("ETag", "\"etag1\"");
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         final ClassicHttpRequest req3 = new BasicClassicHttpRequest("GET", "/");
         req3.setHeader("User-Agent", "agent2");
 
         replayMocks();
         execute(req1);
         execute(req2);
         execute(req3);
         verifyMocks();
     }
 
     /* "If any of the existing cache entries contains only partial content
      * for the associated entity, its entity-tag SHOULD NOT be included in
      * the If-None-Match header field unless the request is for a range
      * that would be fully satisfied by that entry."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.6
      */
     @Test
     public void variantNegotiationsDoNotIncludeEtagsForPartialResponses() throws Exception {
         final ClassicHttpRequest req1 = HttpTestUtils.makeDefaultRequest();
         req1.setHeader("User-Agent", "agent1");
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Cache-Control", "max-age=3600");
         resp1.setHeader("Vary", "User-Agent");
         resp1.setHeader("ETag", "\"etag1\"");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = HttpTestUtils.makeDefaultRequest();
         req2.setHeader("User-Agent", "agent2");
         req2.setHeader("Range", "bytes=0-49");
         final ClassicHttpResponse resp2 = new BasicClassicHttpResponse(HttpStatus.SC_PARTIAL_CONTENT, "Partial Content");
         resp2.setEntity(HttpTestUtils.makeBody(50));
         resp2.setHeader("Content-Length","50");
         resp2.setHeader("Content-Range","bytes 0-49/100");
         resp2.setHeader("Vary","User-Agent");
         resp2.setHeader("ETag", "\"etag2\"");
         resp2.setHeader("Cache-Control","max-age=3600");
         resp2.setHeader("Date", DateUtils.formatDate(new Date()));
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         final ClassicHttpRequest req3 = HttpTestUtils.makeDefaultRequest();
         req3.setHeader("User-Agent", "agent3");
 
         final ClassicHttpResponse resp3 = HttpTestUtils.make200Response();
         resp1.setHeader("Cache-Control", "max-age=3600");
         resp1.setHeader("Vary", "User-Agent");
         resp1.setHeader("ETag", "\"etag3\"");
 
         final Capture<ClassicHttpRequest> cap = EasyMock.newCapture();
         EasyMock.expect(
                 mockExecChain.proceed(
                         EasyMock.capture(cap),
                         EasyMock.isA(ExecChain.Scope.class))).andReturn(resp3);
 
         replayMocks();
         execute(req1);
         execute(req2);
         execute(req3);
         verifyMocks();
 
         final ClassicHttpRequest captured = cap.getValue();
         final Iterator<HeaderElement> it = MessageSupport.iterate(captured, HttpHeaders.IF_NONE_MATCH);
         while (it.hasNext()) {
             final HeaderElement elt = it.next();
             assertFalse("\"etag2\"".equals(elt.toString()));
         }
     }
 
     /* "If a cache receives a successful response whose Content-Location
      * field matches that of an existing cache entry for the same Request-
      * URI, whose entity-tag differs from that of the existing entry, and
      * whose Date is more recent than that of the existing entry, the
      * existing entry SHOULD NOT be returned in response to future requests
      * and SHOULD be deleted from the cache.
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.6
      */
     @Test
     public void cachedEntryShouldNotBeUsedIfMoreRecentMentionInContentLocation() throws Exception {
         final ClassicHttpRequest req1 = new HttpGet("http://foo.example.com/");
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Cache-Control","max-age=3600");
         resp1.setHeader("ETag", "\"old-etag\"");
         resp1.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = new HttpPost("http://foo.example.com/bar");
         final ClassicHttpResponse resp2 = HttpTestUtils.make200Response();
         resp2.setHeader("ETag", "\"new-etag\"");
         resp2.setHeader("Date", DateUtils.formatDate(now));
         resp2.setHeader("Content-Location", "http://foo.example.com/");
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         final ClassicHttpRequest req3 = new HttpGet("http://foo.example.com");
         final ClassicHttpResponse resp3 = HttpTestUtils.make200Response();
 
         backendExpectsAnyRequestAndReturn(resp3);
 
         replayMocks();
         execute(req1);
         execute(req2);
         execute(req3);
         verifyMocks();
     }
 
     /*
      * "This specifically means that responses from HTTP/1.0 servers for such
      * URIs [those containing a '?' in the rel_path part] SHOULD NOT be taken
      * from a cache."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.9
      */
     @Test
     public void responseToGetWithQueryFrom1_0OriginAndNoExpiresIsNotCached() throws Exception {
         final ClassicHttpRequest req2 = new HttpGet("http://foo.example.com/bar?baz=quux");
         final ClassicHttpResponse resp2 = new BasicClassicHttpResponse(HttpStatus.SC_OK, "OK");
         resp2.setVersion(HttpVersion.HTTP_1_0);
         resp2.setEntity(HttpTestUtils.makeBody(200));
         resp2.setHeader("Content-Length","200");
         resp2.setHeader("Date", DateUtils.formatDate(now));
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         replayMocks();
         execute(req2);
         verifyMocks();
     }
 
     @Test
     public void responseToGetWithQueryFrom1_0OriginVia1_1ProxyAndNoExpiresIsNotCached() throws Exception {
         final ClassicHttpRequest req2 = new HttpGet("http://foo.example.com/bar?baz=quux");
         final ClassicHttpResponse resp2 = new BasicClassicHttpResponse(HttpStatus.SC_OK, "OK");
         resp2.setVersion(HttpVersion.HTTP_1_0);
         resp2.setEntity(HttpTestUtils.makeBody(200));
         resp2.setHeader("Content-Length","200");
         resp2.setHeader("Date", DateUtils.formatDate(now));
         resp2.setHeader("Via","1.0 someproxy");
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         replayMocks();
         execute(req2);
         verifyMocks();
     }
 
     /*
      * "A cache that passes through requests for methods it does not
      * understand SHOULD invalidate any entities referred to by the
      * Request-URI."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.10
      */
     @Test
     public void shouldInvalidateNonvariantCacheEntryForUnknownMethod() throws Exception {
         final ClassicHttpRequest req1 = new BasicClassicHttpRequest("GET", "/");
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Cache-Control","max-age=3600");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = new BasicClassicHttpRequest("FROB", "/");
         final ClassicHttpResponse resp2 = HttpTestUtils.make200Response();
         resp2.setHeader("Cache-Control","max-age=3600");
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         final ClassicHttpRequest req3 = new BasicClassicHttpRequest("GET", "/");
         final ClassicHttpResponse resp3 = HttpTestUtils.make200Response();
         resp3.setHeader("ETag", "\"etag\"");
 
         backendExpectsAnyRequestAndReturn(resp3);
 
         replayMocks();
         execute(req1);
         execute(req2);
         final ClassicHttpResponse result = execute(req3);
         verifyMocks();
 
         assertTrue(HttpTestUtils.semanticallyTransparent(resp3, result));
     }
 
     @Test
     public void shouldInvalidateAllVariantsForUnknownMethod() throws Exception {
         final ClassicHttpRequest req1 = new BasicClassicHttpRequest("GET", "/");
         req1.setHeader("User-Agent", "agent1");
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Cache-Control","max-age=3600");
         resp1.setHeader("Vary", "User-Agent");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = new BasicClassicHttpRequest("GET", "/");
         req2.setHeader("User-Agent", "agent2");
         final ClassicHttpResponse resp2 = HttpTestUtils.make200Response();
         resp2.setHeader("Cache-Control","max-age=3600");
         resp2.setHeader("Vary", "User-Agent");
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         final ClassicHttpRequest req3 = new BasicClassicHttpRequest("FROB", "/");
         req3.setHeader("User-Agent", "agent3");
         final ClassicHttpResponse resp3 = HttpTestUtils.make200Response();
         resp3.setHeader("Cache-Control","max-age=3600");
 
         backendExpectsAnyRequestAndReturn(resp3);
 
         final ClassicHttpRequest req4 = new BasicClassicHttpRequest("GET", "/");
         req4.setHeader("User-Agent", "agent1");
         final ClassicHttpResponse resp4 = HttpTestUtils.make200Response();
         resp4.setHeader("ETag", "\"etag1\"");
 
         backendExpectsAnyRequestAndReturn(resp4);
 
         final ClassicHttpRequest req5 = new BasicClassicHttpRequest("GET", "/");
         req5.setHeader("User-Agent", "agent2");
         final ClassicHttpResponse resp5 = HttpTestUtils.make200Response();
         resp5.setHeader("ETag", "\"etag2\"");
 
         backendExpectsAnyRequestAndReturn(resp5);
 
         replayMocks();
         execute(req1);
         execute(req2);
         execute(req3);
         final ClassicHttpResponse result4 = execute(req4);
         final ClassicHttpResponse result5 = execute(req5);
         verifyMocks();
 
         assertTrue(HttpTestUtils.semanticallyTransparent(resp4, result4));
         assertTrue(HttpTestUtils.semanticallyTransparent(resp5, result5));
     }
 
     /*
      * "If a new cacheable response is received from a resource while any
      * existing responses for the same resource are cached, the cache
      * SHOULD use the new response to reply to the current request."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.12
      */
     @Test
     public void cacheShouldUpdateWithNewCacheableResponse() throws Exception {
         final ClassicHttpRequest req1 = HttpTestUtils.makeDefaultRequest();
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         resp1.setHeader("Cache-Control", "max-age=3600");
         resp1.setHeader("ETag", "\"etag1\"");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = HttpTestUtils.makeDefaultRequest();
         req2.setHeader("Cache-Control", "max-age=0");
         final ClassicHttpResponse resp2 = HttpTestUtils.make200Response();
         resp2.setHeader("Date", DateUtils.formatDate(now));
         resp2.setHeader("Cache-Control", "max-age=3600");
         resp2.setHeader("ETag", "\"etag2\"");
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         final ClassicHttpRequest req3 = HttpTestUtils.makeDefaultRequest();
 
         replayMocks();
         execute(req1);
         execute(req2);
         final ClassicHttpResponse result = execute(req3);
         verifyMocks();
 
         assertTrue(HttpTestUtils.semanticallyTransparent(resp2, result));
     }
 
     /*
      * "Many HTTP/1.0 cache implementations will treat an Expires value
      * that is less than or equal to the response Date value as being
      * equivalent to the Cache-Control response directive 'no-cache'.
      * If an HTTP/1.1 cache receives such a response, and the response
      * does not include a Cache-Control header field, it SHOULD consider
      * the response to be non-cacheable in order to retain compatibility
      * with HTTP/1.0 servers."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9.3
      */
     @Test
     public void expiresEqualToDateWithNoCacheControlIsNotCacheable() throws Exception {
         final ClassicHttpRequest req1 = HttpTestUtils.makeDefaultRequest();
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Date", DateUtils.formatDate(now));
         resp1.setHeader("Expires", DateUtils.formatDate(now));
         resp1.removeHeaders("Cache-Control");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = HttpTestUtils.makeDefaultRequest();
         req2.setHeader("Cache-Control", "max-stale=1000");
         final ClassicHttpResponse resp2 = HttpTestUtils.make200Response();
         resp2.setHeader("ETag", "\"etag2\"");
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         replayMocks();
         execute(req1);
         final ClassicHttpResponse result = execute(req2);
         verifyMocks();
 
         assertTrue(HttpTestUtils.semanticallyTransparent(resp2, result));
     }
 
     @Test
     public void expiresPriorToDateWithNoCacheControlIsNotCacheable() throws Exception {
         final ClassicHttpRequest req1 = HttpTestUtils.makeDefaultRequest();
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Date", DateUtils.formatDate(now));
         resp1.setHeader("Expires", DateUtils.formatDate(tenSecondsAgo));
         resp1.removeHeaders("Cache-Control");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = HttpTestUtils.makeDefaultRequest();
         req2.setHeader("Cache-Control", "max-stale=1000");
         final ClassicHttpResponse resp2 = HttpTestUtils.make200Response();
         resp2.setHeader("ETag", "\"etag2\"");
 
         backendExpectsAnyRequestAndReturn(resp2);
 
         replayMocks();
         execute(req1);
         final ClassicHttpResponse result = execute(req2);
         verifyMocks();
 
         assertTrue(HttpTestUtils.semanticallyTransparent(resp2, result));
     }
 
     /*
      * "If a request includes the no-cache directive, it SHOULD NOT
      * include min-fresh, max-stale, or max-age."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9.4
      */
     @Test
     public void otherFreshnessRequestDirectivesNotAllowedWithNoCache() throws Exception {
         final ClassicHttpRequest req1 = HttpTestUtils.makeDefaultRequest();
         req1.setHeader("Cache-Control", "min-fresh=10, no-cache");
         req1.addHeader("Cache-Control", "max-stale=0, max-age=0");
 
 
         final Capture<ClassicHttpRequest> cap = EasyMock.newCapture();
         EasyMock.expect(
                 mockExecChain.proceed(
                         EasyMock.capture(cap),
                         EasyMock.isA(ExecChain.Scope.class))).andReturn(HttpTestUtils.make200Response());
 
         replayMocks();
         execute(req1);
         verifyMocks();
 
         final ClassicHttpRequest captured = cap.getValue();
         boolean foundNoCache = false;
         boolean foundDisallowedDirective = false;
         final List<String> disallowed =
             Arrays.asList("min-fresh", "max-stale", "max-age");
         final Iterator<HeaderElement> it = MessageSupport.iterate(captured, HttpHeaders.CACHE_CONTROL);
         while (it.hasNext()) {
             final HeaderElement elt = it.next();
             if (disallowed.contains(elt.getName())) {
                 foundDisallowedDirective = true;
             }
             if ("no-cache".equals(elt.getName())) {
                 foundNoCache = true;
             }
         }
         assertTrue(foundNoCache);
         assertFalse(foundDisallowedDirective);
     }
 
     /*
      * "To do this, the client may include the only-if-cached directive in
      * a request. If it receives this directive, a cache SHOULD either
      * respond using a cached entry that is consistent with the other
      * constraints of the request, or respond with a 504 (Gateway Timeout)
      * status."
      *
      * http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9.4
      */
     @Test
     public void cacheMissResultsIn504WithOnlyIfCached() throws Exception {
         final ClassicHttpRequest req = HttpTestUtils.makeDefaultRequest();
         req.setHeader("Cache-Control", "only-if-cached");
 
         replayMocks();
         final ClassicHttpResponse result = execute(req);
         verifyMocks();
 
         assertEquals(HttpStatus.SC_GATEWAY_TIMEOUT,
                 result.getCode());
     }
 
     @Test
     public void cacheHitOkWithOnlyIfCached() throws Exception {
         final ClassicHttpRequest req1 = HttpTestUtils.makeDefaultRequest();
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Cache-Control","max-age=3600");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = HttpTestUtils.makeDefaultRequest();
         req2.setHeader("Cache-Control", "only-if-cached");
 
         replayMocks();
         execute(req1);
         final ClassicHttpResponse result = execute(req2);
         verifyMocks();
 
         assertTrue(HttpTestUtils.semanticallyTransparent(resp1, result));
     }
 
     @Test
     public void returns504ForStaleEntryWithOnlyIfCached() throws Exception {
         final ClassicHttpRequest req1 = HttpTestUtils.makeDefaultRequest();
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         resp1.setHeader("Cache-Control","max-age=5");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = HttpTestUtils.makeDefaultRequest();
         req2.setHeader("Cache-Control", "only-if-cached");
 
         replayMocks();
         execute(req1);
         final ClassicHttpResponse result = execute(req2);
         verifyMocks();
 
         assertEquals(HttpStatus.SC_GATEWAY_TIMEOUT,
                 result.getCode());
     }
 
     @Test
     public void returnsStaleCacheEntryWithOnlyIfCachedAndMaxStale() throws Exception {
 
         final ClassicHttpRequest req1 = HttpTestUtils.makeDefaultRequest();
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         resp1.setHeader("Cache-Control","max-age=5");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = HttpTestUtils.makeDefaultRequest();
         req2.setHeader("Cache-Control", "max-stale=20, only-if-cached");
 
         replayMocks();
         execute(req1);
         final ClassicHttpResponse result = execute(req2);
         verifyMocks();
 
         assertTrue(HttpTestUtils.semanticallyTransparent(resp1, result));
     }
 
     @Test
     public void issues304EvenWithWeakETag() throws Exception {
         final ClassicHttpRequest req1 = HttpTestUtils.makeDefaultRequest();
         final ClassicHttpResponse resp1 = HttpTestUtils.make200Response();
         resp1.setHeader("Date", DateUtils.formatDate(tenSecondsAgo));
         resp1.setHeader("Cache-Control", "max-age=300");
         resp1.setHeader("ETag","W/\"weak-sauce\"");
 
         backendExpectsAnyRequestAndReturn(resp1);
 
         final ClassicHttpRequest req2 = HttpTestUtils.makeDefaultRequest();
         req2.setHeader("If-None-Match","W/\"weak-sauce\"");
 
         replayMocks();
         execute(req1);
         final ClassicHttpResponse result = execute(req2);
         verifyMocks();
 
         assertEquals(HttpStatus.SC_NOT_MODIFIED, result.getCode());
 
     }
 
 }