[NTP Snippets] Refactor home-grown container API

components/ntp_snippets/ntp_snippets_service_unittest.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/ntp_snippets/ntp_snippets_service.h"
 
 #include <memory>
 #include <vector>
 
 #include "base/command_line.h"
@@ skipping 13 matching lines @@
 #include "components/ntp_snippets/ntp_snippets_scheduler.h"
 #include "components/ntp_snippets/switches.h"
 #include "components/prefs/testing_pref_service.h"
 #include "google_apis/google_api_keys.h"
 #include "net/url_request/test_url_fetcher_factory.h"
 #include "net/url_request/url_request_test_util.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using testing::ElementsAre;
+using testing::Eq;
 using testing::IsEmpty;
+using testing::SizeIs;
 using testing::StartsWith;
 using testing::_;
 
 namespace ntp_snippets {
 
 namespace {
 
+MATCHER_P(UrlEq, value, "") {
+  return arg->url() == GURL(value);
+}
+
 const base::Time::Exploded kDefaultCreationTime = {2015, 11, 4, 25, 13, 46, 45};
 const char kTestContentSnippetsServerFormat[] =
     "https://chromereader-pa.googleapis.com/v1/fetch?key=%s";
 
 base::Time GetDefaultCreationTime() {
   return base::Time::FromUTCExploded(kDefaultCreationTime);
 }
 
 std::string GetTestJson(const std::string& content_creation_time_str,
                         const std::string& expiry_time_str) {
@@ skipping 211 matching lines @@
 };
 
 TEST_F(NTPSnippetsServiceTest, ScheduleIfEnabled) {
   // SetUp() checks that Schedule is called.
 }
 
 TEST_F(NTPSnippetsServiceDisabledTest, Unschedule) {
   // SetUp() checks that Unschedule is called.
 }
 
-TEST_F(NTPSnippetsServiceTest, Loop) {
-  std::string json_str(
-      "{ \"recos\": [ "
-      "  { \"contentInfo\": { \"url\" : \"http://localhost/foobar\" }}"
-      "]}");
-  LoadFromJSONString(json_str);
-
-  // The same for loop without the '&' should not compile.
-  for (auto& snippet : *service()) {
-    // Snippet here is a const.
-    EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
-  }
-  // Without the const, this should not compile.
-  for (const NTPSnippet& snippet : *service()) {
-    EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
-  }
-}
-
 TEST_F(NTPSnippetsServiceTest, Full) {
   std::string json_str(GetTestJson());
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 1u);
-
-  // The same for loop without the '&' should not compile.
-  for (auto& snippet : *service()) {
-    // Snippet here is a const.
-    EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
-    EXPECT_EQ(snippet.best_source().publisher_name, "Foo News");
-    EXPECT_EQ(snippet.title(), "Title");
-    EXPECT_EQ(snippet.snippet(), "Snippet");
-    EXPECT_EQ(snippet.salient_image_url(),
-              GURL("http://localhost/salient_image"));
-    EXPECT_EQ(GetDefaultCreationTime(), snippet.publish_date());
-    EXPECT_EQ(snippet.best_source().amp_url.spec(),
-              GURL("http://localhost/amp").spec());
-  }
+  ASSERT_THAT(service()->snippets(), SizeIs(1));
+  const NTPSnippet& snippet = *service()->snippets().front();
+  EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
+  EXPECT_EQ(snippet.best_source().publisher_name, "Foo News");
+  EXPECT_EQ(snippet.title(), "Title");
+  EXPECT_EQ(snippet.snippet(), "Snippet");
+  EXPECT_EQ(snippet.salient_image_url(),
+            GURL("http://localhost/salient_image"));
+  EXPECT_EQ(GetDefaultCreationTime(), snippet.publish_date());
+  EXPECT_EQ(snippet.best_source().amp_url.spec(),
+            GURL("http://localhost/amp").spec());
 }
 
 TEST_F(NTPSnippetsServiceTest, Clear) {
   std::string json_str(GetTestJson());
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 1u);
+  EXPECT_THAT(service()->snippets(), SizeIs(1));
 
   service()->ClearSnippets();
-  EXPECT_EQ(service()->size(), 0u);
+  EXPECT_THAT(service()->snippets(), IsEmpty());
 }
 
 TEST_F(NTPSnippetsServiceTest, InsertAtFront) {
   base::Time expiry_time = base::Time::Now() + base::TimeDelta::FromHours(1);
   char json_str_format[] =
       "{ \"recos\": [ "
       "{ \"contentInfo\": {"
       "\"url\" : \"%s\","
       "\"title\" : \"Title\","
       "\"snippet\" : \"Snippet\","
       "\"thumbnailUrl\" : \"http://localhost/salient_image\","
       "\"creationTimestampSec\" : \"%s\","
       "\"expiryTimestampSec\" : \"%s\","
       "\"sourceCorpusInfo\" : [{\"corpusId\": \"http://first\","
       "\"publisherData\": {"
       "\"sourceName\": \"Source 1\""
       "},"
       "\"ampUrl\": \"\"}]"
       "}}"
       "]}";
   std::string json_str(base::StringPrintf(
       json_str_format, "http://first",
       NTPSnippet::TimeToJsonString(GetDefaultCreationTime()).c_str(),
       NTPSnippet::TimeToJsonString(expiry_time).c_str()));
 
   LoadFromJSONString(json_str);
 
-  ASSERT_EQ(service()->size(), 1u);
+  EXPECT_THAT(service()->snippets(), ElementsAre(UrlEq("http://first")));
 
   json_str = base::StringPrintf(
       json_str_format, "http://second",
       NTPSnippet::TimeToJsonString(GetDefaultCreationTime()).c_str(),
       NTPSnippet::TimeToJsonString(expiry_time).c_str());
 
   LoadFromJSONString(json_str);
-  ASSERT_EQ(service()->size(), 2u);
 
   // The snippet loaded last should be at the first position in the list now.
-  const NTPSnippet& first_snippet = *service()->begin();
-  EXPECT_EQ(first_snippet.url(), GURL("http://second"));
+  EXPECT_THAT(service()->snippets(),
+              ElementsAre(UrlEq("http://second"), UrlEq("http://first")));
 }
 
 TEST_F(NTPSnippetsServiceTest, LimitNumSnippets) {
   int max_snippet_count = NTPSnippetsService::GetMaxSnippetCountForTesting();
   int snippets_per_load = max_snippet_count / 2 + 1;
 
   base::Time expiry_time = base::Time::Now() + base::TimeDelta::FromHours(1);
   char json_str_format[] =
       "{ \"contentInfo\": {"
       "\"url\" : \"http://localhost/%i\","
@@ skipping 17 matching lines @@
         NTPSnippet::TimeToJsonString(GetDefaultCreationTime()).c_str(),
         NTPSnippet::TimeToJsonString(expiry_time).c_str()));
     snippets2.push_back(base::StringPrintf(
         json_str_format, snippets_per_load + i,
         NTPSnippet::TimeToJsonString(GetDefaultCreationTime()).c_str(),
         NTPSnippet::TimeToJsonString(expiry_time).c_str()));
   }
 
   LoadFromJSONString(
       "{ \"recos\": [ " + base::JoinString(snippets1, ", ") + "]}");
-  ASSERT_EQ(snippets1.size(), service()->size());
+  ASSERT_THAT(service()->snippets(), SizeIs(snippets1.size()));
 
   LoadFromJSONString(
       "{ \"recos\": [ " + base::JoinString(snippets2, ", ") + "]}");
-  EXPECT_EQ(max_snippet_count, (int)service()->size());
+  EXPECT_THAT(service()->snippets(), SizeIs(max_snippet_count));
 }
 
 TEST_F(NTPSnippetsServiceTest, LoadInvalidJson) {
   LoadFromJSONString(GetInvalidJson());
   EXPECT_THAT(service()->last_status(), StartsWith("Received invalid JSON"));
-  EXPECT_EQ(service()->size(), 0u);
+  EXPECT_THAT(service()->snippets(), IsEmpty());
 }
 
 TEST_F(NTPSnippetsServiceTest, LoadInvalidJsonWithExistingSnippets) {
   LoadFromJSONString(GetTestJson());
-  ASSERT_EQ(service()->size(), 1u);
+  ASSERT_THAT(service()->snippets(), SizeIs(1));
   ASSERT_EQ("OK", service()->last_status());
 
   LoadFromJSONString(GetInvalidJson());
   EXPECT_THAT(service()->last_status(), StartsWith("Received invalid JSON"));
   // This should not have changed the existing snippets.
-  EXPECT_EQ(service()->size(), 1u);
+  EXPECT_THAT(service()->snippets(), SizeIs(1));
 }
 
 TEST_F(NTPSnippetsServiceTest, LoadIncompleteJson) {
   LoadFromJSONString(GetIncompleteJson());
   EXPECT_EQ("Invalid / empty list.", service()->last_status());
-  EXPECT_EQ(service()->size(), 0u);
+  EXPECT_THAT(service()->snippets(), IsEmpty());
 }
 
 TEST_F(NTPSnippetsServiceTest, LoadIncompleteJsonWithExistingSnippets) {
   LoadFromJSONString(GetTestJson());
-  ASSERT_EQ(service()->size(), 1u);
+  ASSERT_THAT(service()->snippets(), SizeIs(1));
 
   LoadFromJSONString(GetIncompleteJson());
   EXPECT_EQ("Invalid / empty list.", service()->last_status());
   // This should not have changed the existing snippets.
-  EXPECT_EQ(service()->size(), 1u);
+  EXPECT_THAT(service()->snippets(), SizeIs(1));
 }
 
 TEST_F(NTPSnippetsServiceTest, Discard) {
   std::vector<std::string> source_urls, publishers, amp_urls;
   source_urls.push_back(std::string("http://site.com"));
   publishers.push_back(std::string("Source 1"));
   amp_urls.push_back(std::string());
   std::string json_str(
       GetTestJsonWithSources(source_urls, publishers, amp_urls));
 
   LoadFromJSONString(json_str);
 
-  ASSERT_EQ(1u, service()->size());
+  ASSERT_THAT(service()->snippets(), SizeIs(1));
 
   // Discarding a non-existent snippet shouldn't do anything.
   EXPECT_FALSE(service()->DiscardSnippet(GURL("http://othersite.com")));
-  EXPECT_EQ(1u, service()->size());
+  EXPECT_THAT(service()->snippets(), SizeIs(1));
 
   // Discard the snippet.
   EXPECT_TRUE(service()->DiscardSnippet(GURL("http://localhost/foobar")));
-  EXPECT_EQ(0u, service()->size());
+  EXPECT_THAT(service()->snippets(), IsEmpty());
 
   // Make sure that fetching the same snippet again does not re-add it.
   LoadFromJSONString(json_str);
-  EXPECT_EQ(0u, service()->size());
+  EXPECT_THAT(service()->snippets(), IsEmpty());
 
   // The snippet should stay discarded even after re-creating the service.
   EXPECT_CALL(mock_scheduler(), Schedule(_, _, _, _)).Times(1);
   CreateSnippetsService(/*enabled=*/true);
   LoadFromJSONString(json_str);
-  EXPECT_EQ(0u, service()->size());
+  EXPECT_THAT(service()->snippets(), IsEmpty());
 
   // The snippet can be added again after clearing discarded snippets.
   service()->ClearDiscardedSnippets();
-  EXPECT_EQ(0u, service()->size());
+  EXPECT_THAT(service()->snippets(), IsEmpty());
   LoadFromJSONString(json_str);
-  EXPECT_EQ(1u, service()->size());
+  EXPECT_THAT(service()->snippets(), SizeIs(1));
 }
 
 TEST_F(NTPSnippetsServiceTest, GetDiscarded) {
   LoadFromJSONString(GetTestJson());
 
   // For the test, we need the snippet to get discarded.
   ASSERT_TRUE(service()->DiscardSnippet(GURL("http://localhost/foobar")));
   const NTPSnippetsService::NTPSnippetStorage& snippets =
       service()->discarded_snippets();
   EXPECT_EQ(1u, snippets.size());
   for (auto& snippet : snippets) {
     EXPECT_EQ(GURL("http://localhost/foobar"), snippet->url());
   }
 
   // There should be no discarded snippet after clearing the list.
   service()->ClearDiscardedSnippets();
   EXPECT_EQ(0u, service()->discarded_snippets().size());
 }
 
 TEST_F(NTPSnippetsServiceTest, CreationTimestampParseFail) {
   std::string json_str(GetTestJson("aaa1448459205"));
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 1u);
-
-  // The same for loop without the '&' should not compile.
-  for (auto& snippet : *service()) {
-    // Snippet here is a const.
-    EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
-    EXPECT_EQ(snippet.title(), "Title");
-    EXPECT_EQ(snippet.snippet(), "Snippet");
-    EXPECT_EQ(base::Time::UnixEpoch(), snippet.publish_date());
-  }
+  ASSERT_THAT(service()->snippets(), SizeIs(1));
+  const NTPSnippet& snippet = *service()->snippets().front();
+  EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
+  EXPECT_EQ(snippet.title(), "Title");
+  EXPECT_EQ(snippet.snippet(), "Snippet");
+  EXPECT_EQ(base::Time::UnixEpoch(), snippet.publish_date());
 }
 
 TEST_F(NTPSnippetsServiceTest, RemoveExpiredContent) {
   std::string json_str(GetTestExpiredJson());
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 0u);
+  EXPECT_THAT(service()->snippets(), IsEmpty());
 }
 
 TEST_F(NTPSnippetsServiceTest, TestSingleSource) {
   std::vector<std::string> source_urls, publishers, amp_urls;
   source_urls.push_back(std::string("http://source1.com"));
   publishers.push_back(std::string("Source 1"));
   amp_urls.push_back(std::string("http://source1.amp.com"));
   std::string json_str(
       GetTestJsonWithSources(source_urls, publishers, amp_urls));
 
   LoadFromJSONString(json_str);
-
-  EXPECT_EQ(service()->size(), 1u);
-
-  for (auto& snippet : *service()) {
-    EXPECT_EQ(snippet.sources().size(), 1u);
-    EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
-    EXPECT_EQ(snippet.best_source().url, GURL("http://source1.com"));
-    EXPECT_EQ(snippet.best_source().publisher_name, std::string("Source 1"));
-    EXPECT_EQ(snippet.best_source().amp_url, GURL("http://source1.amp.com"));
-  }
+  ASSERT_THAT(service()->snippets(), SizeIs(1));
+  const NTPSnippet& snippet = *service()->snippets().front();
+  EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
+  EXPECT_EQ(snippet.best_source().url, GURL("http://source1.com"));
+  EXPECT_EQ(snippet.best_source().publisher_name, std::string("Source 1"));
+  EXPECT_EQ(snippet.best_source().amp_url, GURL("http://source1.amp.com"));
 }
 
 TEST_F(NTPSnippetsServiceTest, TestSingleSourceWithMalformedUrl) {
   std::vector<std::string> source_urls, publishers, amp_urls;
   source_urls.push_back(std::string("aaaa"));
   publishers.push_back(std::string("Source 1"));
   amp_urls.push_back(std::string("http://source1.amp.com"));
   std::string json_str(
       GetTestJsonWithSources(source_urls, publishers, amp_urls));
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 0u);
+  EXPECT_THAT(service()->snippets(), IsEmpty());
 }
 
 TEST_F(NTPSnippetsServiceTest, TestSingleSourceWithMissingData) {
   std::vector<std::string> source_urls, publishers, amp_urls;
   source_urls.push_back(std::string("http://source1.com"));
   publishers.push_back(std::string());
   amp_urls.push_back(std::string());
   std::string json_str(
       GetTestJsonWithSources(source_urls, publishers, amp_urls));
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 0u);
+  EXPECT_THAT(service()->snippets(), IsEmpty());
 }
 
 TEST_F(NTPSnippetsServiceTest, TestMultipleSources) {
   std::vector<std::string> source_urls, publishers, amp_urls;
   source_urls.push_back(std::string("http://source1.com"));
   source_urls.push_back(std::string("http://source2.com"));
   publishers.push_back(std::string("Source 1"));
   publishers.push_back(std::string("Source 2"));
   amp_urls.push_back(std::string("http://source1.amp.com"));
   amp_urls.push_back(std::string("http://source2.amp.com"));
   std::string json_str(
       GetTestJsonWithSources(source_urls, publishers, amp_urls));
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 1u);
-
+  ASSERT_THAT(service()->snippets(), SizeIs(1));
+  const NTPSnippet& snippet = *service()->snippets().front();
   // Expect the first source to be chosen
-  for (auto& snippet : *service()) {
-    EXPECT_EQ(snippet.sources().size(), 2u);
-    EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
-    EXPECT_EQ(snippet.best_source().url, GURL("http://source1.com"));
-    EXPECT_EQ(snippet.best_source().publisher_name, std::string("Source 1"));
-    EXPECT_EQ(snippet.best_source().amp_url, GURL("http://source1.amp.com"));
-  }
+  EXPECT_EQ(snippet.sources().size(), 2u);
+  EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
+  EXPECT_EQ(snippet.best_source().url, GURL("http://source1.com"));
+  EXPECT_EQ(snippet.best_source().publisher_name, std::string("Source 1"));
+  EXPECT_EQ(snippet.best_source().amp_url, GURL("http://source1.amp.com"));
 }
 
 TEST_F(NTPSnippetsServiceTest, TestMultipleIncompleteSources) {
   // Set Source 2 to have no AMP url, and Source 1 to have no publisher name
   // Source 2 should win since we favor publisher name over amp url
   std::vector<std::string> source_urls, publishers, amp_urls;
   source_urls.push_back(std::string("http://source1.com"));
   source_urls.push_back(std::string("http://source2.com"));
   publishers.push_back(std::string());
   publishers.push_back(std::string("Source 2"));
   amp_urls.push_back(std::string("http://source1.amp.com"));
   amp_urls.push_back(std::string());
   std::string json_str(
       GetTestJsonWithSources(source_urls, publishers, amp_urls));
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 1u);
-
-  for (auto& snippet : *service()) {
+  ASSERT_THAT(service()->snippets(), SizeIs(1));
+  {
+    const NTPSnippet& snippet = *service()->snippets().front();
     EXPECT_EQ(snippet.sources().size(), 2u);
     EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
     EXPECT_EQ(snippet.best_source().url, GURL("http://source2.com"));
     EXPECT_EQ(snippet.best_source().publisher_name, std::string("Source 2"));
     EXPECT_EQ(snippet.best_source().amp_url, GURL());
   }
 
   service()->ClearSnippets();
   // Set Source 1 to have no AMP url, and Source 2 to have no publisher name
   // Source 1 should win in this case since we prefer publisher name to AMP url
   source_urls.clear();
   source_urls.push_back(std::string("http://source1.com"));
   source_urls.push_back(std::string("http://source2.com"));
   publishers.clear();
   publishers.push_back(std::string("Source 1"));
   publishers.push_back(std::string());
   amp_urls.clear();
   amp_urls.push_back(std::string());
   amp_urls.push_back(std::string("http://source2.amp.com"));
   json_str = GetTestJsonWithSources(source_urls, publishers, amp_urls);
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 1u);
-
-  for (auto& snippet : *service()) {
+  ASSERT_THAT(service()->snippets(), SizeIs(1));
+  {
+    const NTPSnippet& snippet = *service()->snippets().front();
     EXPECT_EQ(snippet.sources().size(), 2u);
     EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
     EXPECT_EQ(snippet.best_source().url, GURL("http://source1.com"));
     EXPECT_EQ(snippet.best_source().publisher_name, std::string("Source 1"));
     EXPECT_EQ(snippet.best_source().amp_url, GURL());
   }
 
   service()->ClearSnippets();
   // Set source 1 to have no AMP url and no source, and source 2 to only have
   // amp url. There should be no snippets since we only add sources we consider
   // complete
   source_urls.clear();
   source_urls.push_back(std::string("http://source1.com"));
   source_urls.push_back(std::string("http://source2.com"));
   publishers.clear();
   publishers.push_back(std::string());
   publishers.push_back(std::string());
   amp_urls.clear();
   amp_urls.push_back(std::string());
   amp_urls.push_back(std::string("http://source2.amp.com"));
   json_str = GetTestJsonWithSources(source_urls, publishers, amp_urls);
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 0u);
+  EXPECT_THAT(service()->snippets(), IsEmpty());
 }
 
 TEST_F(NTPSnippetsServiceTest, TestMultipleCompleteSources) {
   // Test 2 complete sources, we should choose the first complete source
   std::vector<std::string> source_urls, publishers, amp_urls;
   source_urls.push_back(std::string("http://source1.com"));
   source_urls.push_back(std::string("http://source2.com"));
   source_urls.push_back(std::string("http://source3.com"));
   publishers.push_back(std::string("Source 1"));
   publishers.push_back(std::string());
   publishers.push_back(std::string("Source 3"));
   amp_urls.push_back(std::string("http://source1.amp.com"));
   amp_urls.push_back(std::string("http://source2.amp.com"));
   amp_urls.push_back(std::string("http://source3.amp.com"));
   std::string json_str(
       GetTestJsonWithSources(source_urls, publishers, amp_urls));
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 1u);
-
-  for (auto& snippet : *service()) {
+  ASSERT_THAT(service()->snippets(), SizeIs(1));
+  {
+    const NTPSnippet& snippet = *service()->snippets().front();
     EXPECT_EQ(snippet.sources().size(), 3u);
     EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
     EXPECT_EQ(snippet.best_source().url, GURL("http://source1.com"));
     EXPECT_EQ(snippet.best_source().publisher_name, std::string("Source 1"));
     EXPECT_EQ(snippet.best_source().amp_url, GURL("http://source1.amp.com"));
   }
 
   // Test 2 complete sources, we should choose the first complete source
   service()->ClearSnippets();
   source_urls.clear();
   source_urls.push_back(std::string("http://source1.com"));
   source_urls.push_back(std::string("http://source2.com"));
   source_urls.push_back(std::string("http://source3.com"));
   publishers.clear();
   publishers.push_back(std::string());
   publishers.push_back(std::string("Source 2"));
   publishers.push_back(std::string("Source 3"));
   amp_urls.clear();
   amp_urls.push_back(std::string("http://source1.amp.com"));
   amp_urls.push_back(std::string("http://source2.amp.com"));
   amp_urls.push_back(std::string("http://source3.amp.com"));
   json_str = GetTestJsonWithSources(source_urls, publishers, amp_urls);
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 1u);
-
-  for (auto& snippet : *service()) {
+  ASSERT_THAT(service()->snippets(), SizeIs(1));
+  {
+    const NTPSnippet& snippet = *service()->snippets().front();
     EXPECT_EQ(snippet.sources().size(), 3u);
     EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
     EXPECT_EQ(snippet.best_source().url, GURL("http://source2.com"));
     EXPECT_EQ(snippet.best_source().publisher_name, std::string("Source 2"));
     EXPECT_EQ(snippet.best_source().amp_url, GURL("http://source2.amp.com"));
   }
 
   // Test 3 complete sources, we should choose the first complete source
   service()->ClearSnippets();
   source_urls.clear();
   source_urls.push_back(std::string("http://source1.com"));
   source_urls.push_back(std::string("http://source2.com"));
   source_urls.push_back(std::string("http://source3.com"));
   publishers.clear();
   publishers.push_back(std::string("Source 1"));
   publishers.push_back(std::string("Source 2"));
   publishers.push_back(std::string("Source 3"));
   amp_urls.clear();
   amp_urls.push_back(std::string());
   amp_urls.push_back(std::string("http://source2.amp.com"));
   amp_urls.push_back(std::string("http://source3.amp.com"));
   json_str = GetTestJsonWithSources(source_urls, publishers, amp_urls);
 
   LoadFromJSONString(json_str);
-  EXPECT_EQ(service()->size(), 1u);
-
-  for (auto& snippet : *service()) {
+  ASSERT_THAT(service()->snippets(), SizeIs(1));
+  {
+    const NTPSnippet& snippet = *service()->snippets().front();
     EXPECT_EQ(snippet.sources().size(), 3u);
     EXPECT_EQ(snippet.url(), GURL("http://localhost/foobar"));
     EXPECT_EQ(snippet.best_source().url, GURL("http://source2.com"));
     EXPECT_EQ(snippet.best_source().publisher_name, std::string("Source 2"));
     EXPECT_EQ(snippet.best_source().amp_url, GURL("http://source2.amp.com"));
   }
 }
 
 TEST_F(NTPSnippetsServiceTest, LogNumArticlesHistogram) {
   base::HistogramTester tester;
@@ skipping 42 matching lines @@
   EXPECT_THAT(
       tester.GetAllSamples("NewTabPage.Snippets.NumArticlesZeroDueToDiscarded"),
       ElementsAre(base::Bucket(/*min=*/1, /*count=*/1)));
   // Recreating the service and loading from prefs shouldn't count as fetched
   // articles.
   EXPECT_CALL(mock_scheduler(), Schedule(_, _, _, _)).Times(1);
   CreateSnippetsService(/*enabled=*/true);
   tester.ExpectTotalCount("NewTabPage.Snippets.NumArticlesFetched", 4);
 }
 }  // namespace ntp_snippets