src/net/instaweb/rewriter/insert_dns_prefetch_filter_test.cc - incubator-pagespeed-debian - Git at Google

 /*
  * Copyright 2012 Google Inc.
  *
  * Licensed 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.
  */
 // Author: bharathbhushan@google.com (Bharath Bhushan)

 #include "net/instaweb/rewriter/public/insert_dns_prefetch_filter.h"

 #include "base/logging.h"
 #include "net/instaweb/http/public/log_record.h"
 #include "net/instaweb/http/public/logging_proto_impl.h"
 #include "net/instaweb/rewriter/flush_early.pb.h"
 #include "net/instaweb/rewriter/public/rewrite_driver.h"
 #include "net/instaweb/rewriter/public/rewrite_options.h"
 #include "net/instaweb/rewriter/public/rewrite_test_base.h"
 #include "net/instaweb/rewriter/public/server_context.h"
 #include "pagespeed/kernel/base/gtest.h"
 #include "pagespeed/kernel/base/scoped_ptr.h"
 #include "pagespeed/kernel/base/string.h"
 #include "pagespeed/kernel/base/string_util.h"
 #include "pagespeed/kernel/base/string_writer.h"
 #include "pagespeed/kernel/base/timer.h"
 #include "pagespeed/kernel/http/response_headers.h"
 #include "pagespeed/kernel/http/user_agent_matcher_test_base.h"
 #include "pagespeed/opt/logging/enums.pb.h"

 // TODO(bharathbhushan): Test interaction with the flush early flow and related
 // filters.
 // TODO(bharathbhushan): Have a test to ensure that this is the last post render
 // filter.
 // TODO(bharathbhushan): Add a test for noscript.

 namespace {
 const int64 kOriginTtlMs = 12 * net_instaweb::Timer::kMinuteMs;
 const char kJsData[] =
     "alert     (    'hello, world!'    ) "
     " /* removed */ <!-- removed --> "
     " // single-line-comment";
 }

 namespace net_instaweb {

 class InsertDnsPrefetchFilterTest : public RewriteTestBase {
  public:
   InsertDnsPrefetchFilterTest() : writer_(&output_) {}

  protected:
   virtual void SetUp() {
     options()->set_support_noscript_enabled(false);
     options()->EnableFilter(RewriteOptions::kInsertDnsPrefetch);
     RewriteTestBase::SetUp();
     rewrite_driver()->AddFilters();
     rewrite_driver()->SetWriter(&writer_);
     SetCurrentUserAgent(UserAgentMatcherTestBase::kChromeUserAgent);
   }

   virtual void TearDown() {
     filter_.reset(NULL);
     RewriteTestBase::TearDown();
   }

   void CheckPrefetchInfo(int num_domains_in_current_rewrite,
              int num_domains_in_previous_rewrite,
              int num_domains_to_store, const GoogleString& stored_domains_str) {
     StringPieceVector stored_domains;
     SplitStringPieceToVector(stored_domains_str, ",", &stored_domains, true);
     ASSERT_EQ(num_domains_to_store, stored_domains.size());
     FlushEarlyInfo* info = rewrite_driver()->flush_early_info();
     EXPECT_EQ(num_domains_in_current_rewrite,
               info->total_dns_prefetch_domains());
     EXPECT_EQ(num_domains_in_previous_rewrite,
               info->total_dns_prefetch_domains_previous());
     EXPECT_EQ(num_domains_to_store, info->dns_prefetch_domains_size());
     for (int i = 0; i < info->dns_prefetch_domains_size(); ++i) {
       EXPECT_EQ(stored_domains[i], info->dns_prefetch_domains(i));
     }
   }

   void CheckLogStatus(RewriterHtmlApplication::Status html_status) {
     rewrite_driver_->log_record()->WriteLog();
     for (int i = 0; i < logging_info()->rewriter_stats_size(); i++) {
       if (logging_info()->rewriter_stats(i).id() ==
           RewriteOptions::FilterId(RewriteOptions::kInsertDnsPrefetch) &&
           logging_info()->rewriter_stats(i).has_html_status()) {
         EXPECT_EQ(html_status, logging_info()->rewriter_stats(i).html_status());
         return;
       }
     }
     FAIL();
   }

   void CheckLogStatus(RewriterHtmlApplication::Status html_status,
                       RewriterApplication::Status app_status,
                       int app_status_count) {
     rewrite_driver_->log_record()->WriteLog();
     for (int i = 0; i < logging_info()->rewriter_stats_size(); i++) {
       if (logging_info()->rewriter_stats(i).id() ==
           RewriteOptions::FilterId(RewriteOptions::kInsertDnsPrefetch) &&
           logging_info()->rewriter_stats(i).has_html_status()) {
         EXPECT_EQ(html_status, logging_info()->rewriter_stats(i).html_status());
         const RewriteStatusCount& count_applied =
             logging_info()->rewriter_stats(i).status_counts(0);
         EXPECT_EQ(app_status, count_applied.application_status());
         EXPECT_EQ(app_status_count, count_applied.count());
         return;
       }
     }
     FAIL();
   }

   GoogleString CreateHtml(int num_scripts) {
     GoogleString html = "<head><script></script></head><body>";
     for (int i = 1; i <= num_scripts; ++i) {
       StrAppend(&html, "<script src=\"http://", IntegerToString(i),
                 ".com/\"/>");
     }
     StrAppend(&html, "</body>");
     return html;
   }

   GoogleString CreateHtmlWithPrefetchTags(int num_scripts, int num_tags) {
     GoogleString html = "<head><script></script>";
     for (int i = 1; i <= num_tags; ++i) {
       StrAppend(&html, "<link rel=\"dns-prefetch\" href=\"//",
                 IntegerToString(i), ".com\">");
     }
     StrAppend(&html, "</head><body>");
     for (int i = 1; i <= num_scripts; ++i) {
       StrAppend(&html, "<script src=\"http://", IntegerToString(i),
                 ".com/\"/>");
     }
     html += "</body>";
     return html;
   }

   GoogleString CreateDomainsVector(int num_domains) {
     GoogleString result;
     for (int i = 1; i <= num_domains; ++i) {
       StrAppend(&result, IntegerToString(i), ".com,");
     }
     LOG(INFO) << "CreateDomainsVector: " << result;
     return result;
   }

   GoogleString output_;

  private:
   StringWriter writer_;
   ResponseHeaders headers_;
   scoped_ptr<InsertDnsPrefetchFilter> filter_;

   DISALLOW_COPY_AND_ASSIGN(InsertDnsPrefetchFilterTest);
 };

 TEST_F(InsertDnsPrefetchFilterTest, IgnoreDomainsInHead) {
   GoogleString html =
       "<head>"
         "<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
         "<script src=\"http://b.com/\"/>"
         "<link rel=\"dns-prefetch\" href=\"http://c.com\">"
       "</head><body></body>";
   Parse("ignore_domains_in_head", html);
   EXPECT_EQ(AddHtmlBody(html), output_);
   CheckPrefetchInfo(0, 0, 0, "");
 }

 TEST_F(InsertDnsPrefetchFilterTest, StoreDomainsInBody) {
   GoogleString html =
       "<head></head>"
       "<body>"
         "<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
         "<script src=\"http://b.com/\"/>"
         "<img src=\"http://c.com/\"/>"
       "</body>";
   Parse("store_domains_in_body", html);
   EXPECT_EQ(AddHtmlBody(html), output_);
   CheckPrefetchInfo(3, 0, 3, "a.com,b.com,c.com");
 }

 TEST_F(InsertDnsPrefetchFilterTest, IgnoreCurrentDomain) {
   GoogleString html = StrCat(
       "<head></head>"
       "<body>"
       "<link type=\"text/css\" rel=\"stylesheet\" href=\"",
       AbsolutifyUrl("style.css"),
       "\">"
       "<script src=\"",
       AbsolutifyUrl("script.js"),
       "\">"
       "<img src=\"",
       AbsolutifyUrl("img.src"),
       "\">"
       "</body>");
   Parse("ignore_current_domain", html);
   EXPECT_EQ(AddHtmlBody(html), output_);
   CheckPrefetchInfo(0, 0, 0, "");
 }

 TEST_F(InsertDnsPrefetchFilterTest,
        DisableInsertDnsPrefetchForUserAgentsNotSupported) {
   SetCurrentUserAgent("");
   GoogleString html =
       "<head></head>"
       "<body>"
         "<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
         "<script src=\"http://b.com/\"/>"
         "<img src=\"http://c.com/\"/>"
       "</body>";
   Parse("store_domains_in_body", html);
   EXPECT_EQ(AddHtmlBody(html), output_);
   CheckPrefetchInfo(0, 0, 0, "");
   CheckLogStatus(RewriterHtmlApplication::USER_AGENT_NOT_SUPPORTED);
 }

 TEST_F(InsertDnsPrefetchFilterTest, StoreDomainsOnlyInBody) {
   GoogleString html =
       "<head>"
         "<script src=\"http://b.com/\"/>"
       "</head>"
       "<body>"
         "<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
         "<script src=\"http://b.com/\"/>"
         "<img src=\"http://c.com/\"/>"
       "</body>";
   Parse("store_domains_in_body", html);
   EXPECT_EQ(AddHtmlBody(html), output_);
   // b.com is not stored since it is already in HEAD.
   CheckPrefetchInfo(2, 0, 2, "a.com,c.com");
 }

 TEST_F(InsertDnsPrefetchFilterTest, StoreDomainsInBodyMax) {
   GoogleString html(CreateHtml(10));
   Parse("store_domains_in_body_max", html);
   EXPECT_EQ(AddHtmlBody(html), output_);
   // Only 8/10 domains get stored.
   CheckPrefetchInfo(10, 0, 8, CreateDomainsVector(8));
 }

 // TODO(bharathbhushan): Add tests for all the html tags which can have URI
 // attributes.
 TEST_F(InsertDnsPrefetchFilterTest, LinkTagTest) {
   GoogleString html =
       "<head>"
         "<script></script>"
         "<link rel=\"alternate\" href=\"http://a.com\">"
         "<link rel=\"author\" href=\"http://b.com\">"
         "<link rel=\"dns-prefetch\" href=\"http://c.com\">"
         "<link rel=\"help\" href=\"http://d.com\">"
         "<link rel=\"icon\" href=\"http://e.com\">"
         "<link rel=\"license\" href=\"http://f.com\">"
         "<link rel=\"next\" href=\"http://g.com\">"
         "<link rel=\"prefetch\" href=\"http://h.com\">"
         "<link rel=\"prev\" href=\"http://i.com\">"
         "<link rel=\"search\" href=\"http://j.com\">"
         "<link rel=\"stylesheet\" href=\"http://k.com\">"
       "</head>"
       "<body>"
         "<script src=\"http://a.com/\"/>"
         "<script src=\"http://b.com/\"/>"
         "<script src=\"http://c.com/\"/>"
         "<script src=\"http://d.com/\"/>"
         "<script src=\"http://e.com/\"/>"
         "<script src=\"http://f.com/\"/>"
         "<script src=\"http://g.com/\"/>"
         "<script src=\"http://h.com/\"/>"
         "<script src=\"http://i.com/\"/>"
         "<script src=\"http://j.com/\"/>"
         "<script src=\"http://k.com/\"/>"
       "</body>";
   Parse("test_different_link_tags", html);
   EXPECT_EQ(AddHtmlBody(html), output_);
   // The following link types are for resources or relevant to DNS prefetch
   // tags: dns-prefetch, icon, prefetch, stylesheet. The domains in those tags
   // are not stored. The rest of link types have hyperlinks and their domains
   // get stored.
   CheckPrefetchInfo(7, 0, 7, "a.com,b.com,d.com,f.com,g.com,i.com,j.com");
 }

 TEST_F(InsertDnsPrefetchFilterTest, FullFlowTest) {
   GoogleString html_input = CreateHtml(10);
   Parse("store_8_of_10", html_input);
   EXPECT_EQ(AddHtmlBody(html_input), output_);
   CheckPrefetchInfo(10, 0, 8, CreateDomainsVector(8));
   output_.clear();

   html_input = CreateHtml(9);
   Parse("store_8_of_9", html_input);
   EXPECT_EQ(AddHtmlBody(html_input), output_);
   CheckPrefetchInfo(9, 10, 8, CreateDomainsVector(8));
   output_.clear();

   html_input = CreateHtml(6);
   // 8 DNS prefetch tags inserted since the difference in the number of domains
   // in the last two rewrites (10, 9) is <= 2 and we had stored 8 domains in the
   // previous rewrite. This is the common case.
   // In this rewrite we have an unstable response, whose effect shows up in the
   // next rewrite.
   GoogleString html_output = CreateHtmlWithPrefetchTags(6, 8);
   Parse("stable_domain_list_so_insert_tags", html_input);
   EXPECT_EQ(AddHtmlBody(html_output), output_);
   CheckPrefetchInfo(6, 9, 6, CreateDomainsVector(6));
   output_.clear();
   CheckLogStatus(RewriterHtmlApplication::ACTIVE,
                  RewriterApplication::APPLIED_OK,
                  8);

   // Since the last response caused instability in the domain list, we don't
   // insert any prefetch tags in this rewrite.
   Parse("after_unstable_response", html_input);
   EXPECT_EQ(AddHtmlBody(html_input), output_);
   CheckPrefetchInfo(6, 6, 6, CreateDomainsVector(6));
   output_.clear();
 }

 TEST_F(InsertDnsPrefetchFilterTest, FullFlowTestForLogging) {
   GoogleString html_input = CreateHtml(10);
   Parse("store_8_of_10", html_input);
   EXPECT_EQ(AddHtmlBody(html_input), output_);
   CheckPrefetchInfo(10, 0, 8, CreateDomainsVector(8));
   output_.clear();

   html_input = CreateHtml(9);
   Parse("store_8_of_9", html_input);
   EXPECT_EQ(AddHtmlBody(html_input), output_);
   CheckPrefetchInfo(9, 10, 8, CreateDomainsVector(8));
   CheckLogStatus(RewriterHtmlApplication::ACTIVE,
                  RewriterApplication::NOT_APPLIED,
                  1);
   output_.clear();
 }

 TEST_F(InsertDnsPrefetchFilterTest, InsertDnsPrefetchFilterWithOtherFilters) {
   options()->ClearSignatureForTesting();
   options()->EnableFilter(RewriteOptions::kDeferJavascript);
   options()->EnableFilter(RewriteOptions::kLazyloadImages);
   options()->EnableFilter(RewriteOptions::kDelayImages);
   server_context()->ComputeSignature(options());
   GoogleString html =
       "<head>"
         "<script src=\"http://b.com/\"/>"
       "</head>"
       "<body>"
         "<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
         "<script src=\"http://b.com/\"/>"
         "<img src=\"http://c.com/\"/>"
       "</body>";
   Parse("store_domains_in_body", html);
   EXPECT_EQ(AddHtmlBody(html), output_);
   // b.com is not stored since it is already in HEAD.
   CheckPrefetchInfo(2, 0, 2, "a.com,c.com");
 }

 TEST_F(InsertDnsPrefetchFilterTest, InsertDomainsinHeadForFlushEarlyFlow) {
   options()->ClearSignatureForTesting();
   options()->EnableFilter(RewriteOptions::kFlushSubresources);
   server_context()->ComputeSignature(options());
   GoogleString html =
       "<head>"
         "<script src=\"http://b.com/\"/>"
       "<script src=\"http://d.com/\"/>"
       "</head>"
       "<body>"
         "<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
         "<script src=\"http://b.com/\"/>"
         "<img src=\"http://c.com/\"/>"
       "</body>";
   Parse("store_domains_in_body", html);
   EXPECT_EQ(AddHtmlBody(html), output_);
   CheckPrefetchInfo(4, 0, 4, "b.com,d.com,a.com,c.com");
 }

 TEST_F(InsertDnsPrefetchFilterTest, NoDomainsWhileFlushingEarly) {
   rewrite_driver()->set_flushing_early(true);
   GoogleString html =
       "<head>"
         "<script src=\"http://b.com/\"/>"
       "</head>"
       "<body>"
         "<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
         "<script src=\"http://b.com/\"/>"
         "<img src=\"http://c.com/\"/>"
       "</body>";
   Parse("store_domains_in_body", html);
   EXPECT_EQ(AddHtmlBody(html), output_);
   CheckPrefetchInfo(0, 0, 0, "");
 }

 }  // namespace net_instaweb
	/*
	* Copyright 2012 Google Inc.
	*
	* Licensed 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.
	*/
	// Author: bharathbhushan@google.com (Bharath Bhushan)

	#include "net/instaweb/rewriter/public/insert_dns_prefetch_filter.h"

	#include "base/logging.h"
	#include "net/instaweb/http/public/log_record.h"
	#include "net/instaweb/http/public/logging_proto_impl.h"
	#include "net/instaweb/rewriter/flush_early.pb.h"
	#include "net/instaweb/rewriter/public/rewrite_driver.h"
	#include "net/instaweb/rewriter/public/rewrite_options.h"
	#include "net/instaweb/rewriter/public/rewrite_test_base.h"
	#include "net/instaweb/rewriter/public/server_context.h"
	#include "pagespeed/kernel/base/gtest.h"
	#include "pagespeed/kernel/base/scoped_ptr.h"
	#include "pagespeed/kernel/base/string.h"
	#include "pagespeed/kernel/base/string_util.h"
	#include "pagespeed/kernel/base/string_writer.h"
	#include "pagespeed/kernel/base/timer.h"
	#include "pagespeed/kernel/http/response_headers.h"
	#include "pagespeed/kernel/http/user_agent_matcher_test_base.h"
	#include "pagespeed/opt/logging/enums.pb.h"

	// TODO(bharathbhushan): Test interaction with the flush early flow and related
	// filters.
	// TODO(bharathbhushan): Have a test to ensure that this is the last post render
	// filter.
	// TODO(bharathbhushan): Add a test for noscript.

	namespace {
	const int64 kOriginTtlMs = 12 * net_instaweb::Timer::kMinuteMs;
	const char kJsData[] =
	"alert ( 'hello, world!' ) "
	" /* removed */ <!-- removed --> "
	" // single-line-comment";
	}

	namespace net_instaweb {

	class InsertDnsPrefetchFilterTest : public RewriteTestBase {
	public:
	InsertDnsPrefetchFilterTest() : writer_(&output_) {}

	protected:
	virtual void SetUp() {
	options()->set_support_noscript_enabled(false);
	options()->EnableFilter(RewriteOptions::kInsertDnsPrefetch);
	RewriteTestBase::SetUp();
	rewrite_driver()->AddFilters();
	rewrite_driver()->SetWriter(&writer_);
	SetCurrentUserAgent(UserAgentMatcherTestBase::kChromeUserAgent);
	}

	virtual void TearDown() {
	filter_.reset(NULL);
	RewriteTestBase::TearDown();
	}

	void CheckPrefetchInfo(int num_domains_in_current_rewrite,
	int num_domains_in_previous_rewrite,
	int num_domains_to_store, const GoogleString& stored_domains_str) {
	StringPieceVector stored_domains;
	SplitStringPieceToVector(stored_domains_str, ",", &stored_domains, true);
	ASSERT_EQ(num_domains_to_store, stored_domains.size());
	FlushEarlyInfo* info = rewrite_driver()->flush_early_info();
	EXPECT_EQ(num_domains_in_current_rewrite,
	info->total_dns_prefetch_domains());
	EXPECT_EQ(num_domains_in_previous_rewrite,
	info->total_dns_prefetch_domains_previous());
	EXPECT_EQ(num_domains_to_store, info->dns_prefetch_domains_size());
	for (int i = 0; i < info->dns_prefetch_domains_size(); ++i) {
	EXPECT_EQ(stored_domains[i], info->dns_prefetch_domains(i));
	}
	}

	void CheckLogStatus(RewriterHtmlApplication::Status html_status) {
	rewrite_driver_->log_record()->WriteLog();
	for (int i = 0; i < logging_info()->rewriter_stats_size(); i++) {
	if (logging_info()->rewriter_stats(i).id() ==
	RewriteOptions::FilterId(RewriteOptions::kInsertDnsPrefetch) &&
	logging_info()->rewriter_stats(i).has_html_status()) {
	EXPECT_EQ(html_status, logging_info()->rewriter_stats(i).html_status());
	return;
	}
	}
	FAIL();
	}

	void CheckLogStatus(RewriterHtmlApplication::Status html_status,
	RewriterApplication::Status app_status,
	int app_status_count) {
	rewrite_driver_->log_record()->WriteLog();
	for (int i = 0; i < logging_info()->rewriter_stats_size(); i++) {
	if (logging_info()->rewriter_stats(i).id() ==
	RewriteOptions::FilterId(RewriteOptions::kInsertDnsPrefetch) &&
	logging_info()->rewriter_stats(i).has_html_status()) {
	EXPECT_EQ(html_status, logging_info()->rewriter_stats(i).html_status());
	const RewriteStatusCount& count_applied =
	logging_info()->rewriter_stats(i).status_counts(0);
	EXPECT_EQ(app_status, count_applied.application_status());
	EXPECT_EQ(app_status_count, count_applied.count());
	return;
	}
	}
	FAIL();
	}

	GoogleString CreateHtml(int num_scripts) {
	GoogleString html = "<head><script></script></head><body>";
	for (int i = 1; i <= num_scripts; ++i) {
	StrAppend(&html, "<script src=\"http://", IntegerToString(i),
	".com/\"/>");
	}
	StrAppend(&html, "</body>");
	return html;
	}

	GoogleString CreateHtmlWithPrefetchTags(int num_scripts, int num_tags) {
	GoogleString html = "<head><script></script>";
	for (int i = 1; i <= num_tags; ++i) {
	StrAppend(&html, "<link rel=\"dns-prefetch\" href=\"//",
	IntegerToString(i), ".com\">");
	}
	StrAppend(&html, "</head><body>");
	for (int i = 1; i <= num_scripts; ++i) {
	StrAppend(&html, "<script src=\"http://", IntegerToString(i),
	".com/\"/>");
	}
	html += "</body>";
	return html;
	}

	GoogleString CreateDomainsVector(int num_domains) {
	GoogleString result;
	for (int i = 1; i <= num_domains; ++i) {
	StrAppend(&result, IntegerToString(i), ".com,");
	}
	LOG(INFO) << "CreateDomainsVector: " << result;
	return result;
	}

	GoogleString output_;

	private:
	StringWriter writer_;
	ResponseHeaders headers_;
	scoped_ptr<InsertDnsPrefetchFilter> filter_;

	DISALLOW_COPY_AND_ASSIGN(InsertDnsPrefetchFilterTest);
	};

	TEST_F(InsertDnsPrefetchFilterTest, IgnoreDomainsInHead) {
	GoogleString html =
	"<head>"
	"<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
	"<script src=\"http://b.com/\"/>"
	"<link rel=\"dns-prefetch\" href=\"http://c.com\">"
	"</head><body></body>";
	Parse("ignore_domains_in_head", html);
	EXPECT_EQ(AddHtmlBody(html), output_);
	CheckPrefetchInfo(0, 0, 0, "");
	}

	TEST_F(InsertDnsPrefetchFilterTest, StoreDomainsInBody) {
	GoogleString html =
	"<head></head>"
	"<body>"
	"<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
	"<script src=\"http://b.com/\"/>"
	"<img src=\"http://c.com/\"/>"
	"</body>";
	Parse("store_domains_in_body", html);
	EXPECT_EQ(AddHtmlBody(html), output_);
	CheckPrefetchInfo(3, 0, 3, "a.com,b.com,c.com");
	}

	TEST_F(InsertDnsPrefetchFilterTest, IgnoreCurrentDomain) {
	GoogleString html = StrCat(
	"<head></head>"
	"<body>"
	"<link type=\"text/css\" rel=\"stylesheet\" href=\"",
	AbsolutifyUrl("style.css"),
	"\">"
	"<script src=\"",
	AbsolutifyUrl("script.js"),
	"\">"
	"<img src=\"",
	AbsolutifyUrl("img.src"),
	"\">"
	"</body>");
	Parse("ignore_current_domain", html);
	EXPECT_EQ(AddHtmlBody(html), output_);
	CheckPrefetchInfo(0, 0, 0, "");
	}

	TEST_F(InsertDnsPrefetchFilterTest,
	DisableInsertDnsPrefetchForUserAgentsNotSupported) {
	SetCurrentUserAgent("");
	GoogleString html =
	"<head></head>"
	"<body>"
	"<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
	"<script src=\"http://b.com/\"/>"
	"<img src=\"http://c.com/\"/>"
	"</body>";
	Parse("store_domains_in_body", html);
	EXPECT_EQ(AddHtmlBody(html), output_);
	CheckPrefetchInfo(0, 0, 0, "");
	CheckLogStatus(RewriterHtmlApplication::USER_AGENT_NOT_SUPPORTED);
	}

	TEST_F(InsertDnsPrefetchFilterTest, StoreDomainsOnlyInBody) {
	GoogleString html =
	"<head>"
	"<script src=\"http://b.com/\"/>"
	"</head>"
	"<body>"
	"<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
	"<script src=\"http://b.com/\"/>"
	"<img src=\"http://c.com/\"/>"
	"</body>";
	Parse("store_domains_in_body", html);
	EXPECT_EQ(AddHtmlBody(html), output_);
	// b.com is not stored since it is already in HEAD.
	CheckPrefetchInfo(2, 0, 2, "a.com,c.com");
	}

	TEST_F(InsertDnsPrefetchFilterTest, StoreDomainsInBodyMax) {
	GoogleString html(CreateHtml(10));
	Parse("store_domains_in_body_max", html);
	EXPECT_EQ(AddHtmlBody(html), output_);
	// Only 8/10 domains get stored.
	CheckPrefetchInfo(10, 0, 8, CreateDomainsVector(8));
	}

	// TODO(bharathbhushan): Add tests for all the html tags which can have URI
	// attributes.
	TEST_F(InsertDnsPrefetchFilterTest, LinkTagTest) {
	GoogleString html =
	"<head>"
	"<script></script>"
	"<link rel=\"alternate\" href=\"http://a.com\">"
	"<link rel=\"author\" href=\"http://b.com\">"
	"<link rel=\"dns-prefetch\" href=\"http://c.com\">"
	"<link rel=\"help\" href=\"http://d.com\">"
	"<link rel=\"icon\" href=\"http://e.com\">"
	"<link rel=\"license\" href=\"http://f.com\">"
	"<link rel=\"next\" href=\"http://g.com\">"
	"<link rel=\"prefetch\" href=\"http://h.com\">"
	"<link rel=\"prev\" href=\"http://i.com\">"
	"<link rel=\"search\" href=\"http://j.com\">"
	"<link rel=\"stylesheet\" href=\"http://k.com\">"
	"</head>"
	"<body>"
	"<script src=\"http://a.com/\"/>"
	"<script src=\"http://b.com/\"/>"
	"<script src=\"http://c.com/\"/>"
	"<script src=\"http://d.com/\"/>"
	"<script src=\"http://e.com/\"/>"
	"<script src=\"http://f.com/\"/>"
	"<script src=\"http://g.com/\"/>"
	"<script src=\"http://h.com/\"/>"
	"<script src=\"http://i.com/\"/>"
	"<script src=\"http://j.com/\"/>"
	"<script src=\"http://k.com/\"/>"
	"</body>";
	Parse("test_different_link_tags", html);
	EXPECT_EQ(AddHtmlBody(html), output_);
	// The following link types are for resources or relevant to DNS prefetch
	// tags: dns-prefetch, icon, prefetch, stylesheet. The domains in those tags
	// are not stored. The rest of link types have hyperlinks and their domains
	// get stored.
	CheckPrefetchInfo(7, 0, 7, "a.com,b.com,d.com,f.com,g.com,i.com,j.com");
	}

	TEST_F(InsertDnsPrefetchFilterTest, FullFlowTest) {
	GoogleString html_input = CreateHtml(10);
	Parse("store_8_of_10", html_input);
	EXPECT_EQ(AddHtmlBody(html_input), output_);
	CheckPrefetchInfo(10, 0, 8, CreateDomainsVector(8));
	output_.clear();

	html_input = CreateHtml(9);
	Parse("store_8_of_9", html_input);
	EXPECT_EQ(AddHtmlBody(html_input), output_);
	CheckPrefetchInfo(9, 10, 8, CreateDomainsVector(8));
	output_.clear();

	html_input = CreateHtml(6);
	// 8 DNS prefetch tags inserted since the difference in the number of domains
	// in the last two rewrites (10, 9) is <= 2 and we had stored 8 domains in the
	// previous rewrite. This is the common case.
	// In this rewrite we have an unstable response, whose effect shows up in the
	// next rewrite.
	GoogleString html_output = CreateHtmlWithPrefetchTags(6, 8);
	Parse("stable_domain_list_so_insert_tags", html_input);
	EXPECT_EQ(AddHtmlBody(html_output), output_);
	CheckPrefetchInfo(6, 9, 6, CreateDomainsVector(6));
	output_.clear();
	CheckLogStatus(RewriterHtmlApplication::ACTIVE,
	RewriterApplication::APPLIED_OK,
	8);

	// Since the last response caused instability in the domain list, we don't
	// insert any prefetch tags in this rewrite.
	Parse("after_unstable_response", html_input);
	EXPECT_EQ(AddHtmlBody(html_input), output_);
	CheckPrefetchInfo(6, 6, 6, CreateDomainsVector(6));
	output_.clear();
	}

	TEST_F(InsertDnsPrefetchFilterTest, FullFlowTestForLogging) {
	GoogleString html_input = CreateHtml(10);
	Parse("store_8_of_10", html_input);
	EXPECT_EQ(AddHtmlBody(html_input), output_);
	CheckPrefetchInfo(10, 0, 8, CreateDomainsVector(8));
	output_.clear();

	html_input = CreateHtml(9);
	Parse("store_8_of_9", html_input);
	EXPECT_EQ(AddHtmlBody(html_input), output_);
	CheckPrefetchInfo(9, 10, 8, CreateDomainsVector(8));
	CheckLogStatus(RewriterHtmlApplication::ACTIVE,
	RewriterApplication::NOT_APPLIED,
	1);
	output_.clear();
	}

	TEST_F(InsertDnsPrefetchFilterTest, InsertDnsPrefetchFilterWithOtherFilters) {
	options()->ClearSignatureForTesting();
	options()->EnableFilter(RewriteOptions::kDeferJavascript);
	options()->EnableFilter(RewriteOptions::kLazyloadImages);
	options()->EnableFilter(RewriteOptions::kDelayImages);
	server_context()->ComputeSignature(options());
	GoogleString html =
	"<head>"
	"<script src=\"http://b.com/\"/>"
	"</head>"
	"<body>"
	"<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
	"<script src=\"http://b.com/\"/>"
	"<img src=\"http://c.com/\"/>"
	"</body>";
	Parse("store_domains_in_body", html);
	EXPECT_EQ(AddHtmlBody(html), output_);
	// b.com is not stored since it is already in HEAD.
	CheckPrefetchInfo(2, 0, 2, "a.com,c.com");
	}

	TEST_F(InsertDnsPrefetchFilterTest, InsertDomainsinHeadForFlushEarlyFlow) {
	options()->ClearSignatureForTesting();
	options()->EnableFilter(RewriteOptions::kFlushSubresources);
	server_context()->ComputeSignature(options());
	GoogleString html =
	"<head>"
	"<script src=\"http://b.com/\"/>"
	"<script src=\"http://d.com/\"/>"
	"</head>"
	"<body>"
	"<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
	"<script src=\"http://b.com/\"/>"
	"<img src=\"http://c.com/\"/>"
	"</body>";
	Parse("store_domains_in_body", html);
	EXPECT_EQ(AddHtmlBody(html), output_);
	CheckPrefetchInfo(4, 0, 4, "b.com,d.com,a.com,c.com");
	}

	TEST_F(InsertDnsPrefetchFilterTest, NoDomainsWhileFlushingEarly) {
	rewrite_driver()->set_flushing_early(true);
	GoogleString html =
	"<head>"
	"<script src=\"http://b.com/\"/>"
	"</head>"
	"<body>"
	"<link type=\"text/css\" rel=\"stylesheet\" href=\"http://a.com/\">"
	"<script src=\"http://b.com/\"/>"
	"<img src=\"http://c.com/\"/>"
	"</body>";
	Parse("store_domains_in_body", html);
	EXPECT_EQ(AddHtmlBody(html), output_);
	CheckPrefetchInfo(0, 0, 0, "");
	}

	} // namespace net_instaweb