FetchMore functionality backend

components/ntp_snippets/remote/ntp_snippets_fetcher_unittest.cc

 // Copyright 2016 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/remote/ntp_snippets_fetcher.h"
 
 #include <map>
 #include <utility>
 
 #include "base/json/json_reader.h"
@@ skipping 155 matching lines @@
     UserClassifier::RegisterProfilePrefs(pref_service_->registry());
     user_classifier_ = base::MakeUnique<UserClassifier>(pref_service_.get());
 
     snippets_fetcher_ = base::MakeUnique<NTPSnippetsFetcher>(
         fake_signin_manager_.get(), fake_token_service_.get(),
         scoped_refptr<net::TestURLRequestContextGetter>(
             new net::TestURLRequestContextGetter(mock_task_runner_.get())),
         pref_service_.get(), &category_factory_, nullptr,
         base::Bind(&ParseJsonDelayed), kAPIKey, user_classifier_.get());
 
-    snippets_fetcher_->SetCallback(
-        base::Bind(&MockSnippetsAvailableCallback::WrappedRun,
-                   base::Unretained(&mock_callback_)));
     snippets_fetcher_->SetTickClockForTesting(
         mock_task_runner_->GetMockTickClock());
     // Increase initial time such that ticks are non-zero.
     mock_task_runner_->FastForwardBy(base::TimeDelta::FromMilliseconds(1234));
   }
 
+  NTPSnippetsFetcher::SnippetsAvailableCallback MakeMockCallback() {
+    return base::BindOnce(&MockSnippetsAvailableCallback::WrappedRun,
+                          base::Unretained(&mock_callback_));
+  }
+
+  base::Optional<Category> OptionalArticlesCategory() {

[tschumann, 2016/11/03 09:20:57]

we should inline this. It only obfuscates reading the tests and it's actually
quite short to write out.

+    return base::Optional<Category>(
+        CategoryFactory().FromKnownCategory(KnownCategories::ARTICLES));
+  }
+
   NTPSnippetsFetcher& snippets_fetcher() { return *snippets_fetcher_; }
   MockSnippetsAvailableCallback& mock_callback() { return mock_callback_; }
   void FastForwardUntilNoTasksRemain() {
     mock_task_runner_->FastForwardUntilNoTasksRemain();
   }
   base::HistogramTester& histogram_tester() { return histogram_tester_; }
 
   NTPSnippetsFetcher::Params test_params() {
     NTPSnippetsFetcher::Params result;
     result.count_to_fetch = 1;
@@ skipping 306 matching lines @@
       "    \"sourceCorpusInfo\" : [{"
       "      \"ampUrl\" : \"http://localhost/amp\","
       "      \"corpusId\" : \"http://localhost/foobar\","
       "      \"publisherData\": { \"sourceName\" : \"Foo News\" }"
       "    }]"
       "  }"
       "}]}";
   SetFakeResponse(/*response_data=*/kJsonStr, net::HTTP_OK,
                   net::URLRequestStatus::SUCCESS);
   EXPECT_CALL(mock_callback(), Run(IsSingleArticle("http://localhost/foobar")));
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   FastForwardUntilNoTasksRemain();
   EXPECT_THAT(snippets_fetcher().last_status(), Eq("OK"));
   EXPECT_THAT(snippets_fetcher().last_json(), Eq(kJsonStr));
   EXPECT_THAT(histogram_tester().GetAllSamples(
                   "NewTabPage.Snippets.FetchHttpResponseOrErrorCode"),
               ElementsAre(base::Bucket(/*min=*/200, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchTime"),
               ElementsAre(base::Bucket(/*min=*/kTestJsonParsingLatencyMs,
                                        /*count=*/1)));
 }
@@ skipping 12 matching lines @@
       "    \"expirationTime\" : \"2016-07-01T11:01:37.000Z\","
       "    \"attribution\" : \"Foo News\","
       "    \"imageUrl\" : \"http://localhost/foobar.jpg\","
       "    \"ampUrl\" : \"http://localhost/amp\","
       "    \"faviconUrl\" : \"http://localhost/favicon.ico\" "
       "  }]"
       "}]}";
   SetFakeResponse(/*response_data=*/kJsonStr, net::HTTP_OK,
                   net::URLRequestStatus::SUCCESS);
   EXPECT_CALL(mock_callback(), Run(IsSingleArticle("http://localhost/foobar")));
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   FastForwardUntilNoTasksRemain();
   EXPECT_THAT(snippets_fetcher().last_status(), Eq("OK"));
   EXPECT_THAT(snippets_fetcher().last_json(), Eq(kJsonStr));
   EXPECT_THAT(histogram_tester().GetAllSamples(
                   "NewTabPage.Snippets.FetchHttpResponseOrErrorCode"),
               ElementsAre(base::Bucket(/*min=*/200, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchTime"),
               ElementsAre(base::Bucket(/*min=*/kTestJsonParsingLatencyMs,
                                        /*count=*/1)));
 }
 
 TEST_F(NTPSnippetsContentSuggestionsFetcherTest, EmptyCategoryIsOK) {
   const std::string kJsonStr =
       "{\"categories\" : [{"
       "  \"id\": 1,"
       "  \"localizedTitle\": \"Articles for You\""
       "}]}";
   SetFakeResponse(/*response_data=*/kJsonStr, net::HTTP_OK,
                   net::URLRequestStatus::SUCCESS);
   EXPECT_CALL(mock_callback(), Run(IsEmptyArticleList()));
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   FastForwardUntilNoTasksRemain();
   EXPECT_THAT(snippets_fetcher().last_status(), Eq("OK"));
   EXPECT_THAT(snippets_fetcher().last_json(), Eq(kJsonStr));
   EXPECT_THAT(histogram_tester().GetAllSamples(
                   "NewTabPage.Snippets.FetchHttpResponseOrErrorCode"),
               ElementsAre(base::Bucket(/*min=*/200, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchTime"),
               ElementsAre(base::Bucket(/*min=*/kTestJsonParsingLatencyMs,
                                        /*count=*/1)));
 }
@@ skipping 29 matching lines @@
       "    \"imageUrl\" : \"http://localhost/foo2.jpg\","
       "    \"ampUrl\" : \"http://localhost/amp\","
       "    \"faviconUrl\" : \"http://localhost/favicon.ico\" "
       "  }]"
       "}]}";
   SetFakeResponse(/*response_data=*/kJsonStr, net::HTTP_OK,
                   net::URLRequestStatus::SUCCESS);
   NTPSnippetsFetcher::OptionalFetchedCategories fetched_categories;
   EXPECT_CALL(mock_callback(), Run(_))
       .WillOnce(WithArg<0>(MovePointeeTo(&fetched_categories)));
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   FastForwardUntilNoTasksRemain();
 
   ASSERT_TRUE(fetched_categories);
   ASSERT_THAT(fetched_categories->size(), Eq(2u));
   for (const auto& category : *fetched_categories) {
     const auto& articles = category.snippets;
     switch (category.category.id()) {
       case static_cast<int>(KnownCategories::ARTICLES):
         ASSERT_THAT(articles.size(), Eq(1u));
         EXPECT_THAT(articles[0]->best_source().url.spec(),
@@ skipping 12 matching lines @@
   EXPECT_THAT(snippets_fetcher().last_status(), Eq("OK"));
   EXPECT_THAT(snippets_fetcher().last_json(), Eq(kJsonStr));
   EXPECT_THAT(histogram_tester().GetAllSamples(
                   "NewTabPage.Snippets.FetchHttpResponseOrErrorCode"),
               ElementsAre(base::Bucket(/*min=*/200, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchTime"),
               ElementsAre(base::Bucket(/*min=*/kTestJsonParsingLatencyMs,
                                        /*count=*/1)));
 }
 
+TEST_F(NTPSnippetsContentSuggestionsFetcherTest, ExclusiveCategoryOnly) {
+  const std::string kJsonStr =
+      "{\"categories\" : [{"
+      "  \"id\": 1,"
+      "  \"localizedTitle\": \"Articles for You\","
+      "  \"suggestions\" : [{"
+      "    \"ids\" : [\"http://localhost/foobar\"],"
+      "    \"title\" : \"Foo Barred from Baz\","
+      "    \"snippet\" : \"...\","
+      "    \"fullPageUrl\" : \"http://localhost/foobar\","
+      "    \"creationTime\" : \"2016-06-30T11:01:37.000Z\","
+      "    \"expirationTime\" : \"2016-07-01T11:01:37.000Z\","
+      "    \"attribution\" : \"Foo News\","
+      "    \"imageUrl\" : \"http://localhost/foobar.jpg\","
+      "    \"ampUrl\" : \"http://localhost/amp\","
+      "    \"faviconUrl\" : \"http://localhost/favicon.ico\" "
+      "  }]"
+      "}, {"
+      "  \"id\": 2,"
+      "  \"localizedTitle\": \"Articles for Me\","
+      "  \"suggestions\" : [{"
+      "    \"ids\" : [\"http://localhost/foo2\"],"
+      "    \"title\" : \"Foo Barred from Baz\","
+      "    \"snippet\" : \"...\","
+      "    \"fullPageUrl\" : \"http://localhost/foo2\","
+      "    \"creationTime\" : \"2016-06-30T11:01:37.000Z\","
+      "    \"expirationTime\" : \"2016-07-01T11:01:37.000Z\","
+      "    \"attribution\" : \"Foo News\","
+      "    \"imageUrl\" : \"http://localhost/foo2.jpg\","
+      "    \"ampUrl\" : \"http://localhost/amp\","
+      "    \"faviconUrl\" : \"http://localhost/favicon.ico\" "
+      "  }]"
+      "}]}";
+  SetFakeResponse(/*response_data=*/kJsonStr, net::HTTP_OK,
+                  net::URLRequestStatus::SUCCESS);
+  NTPSnippetsFetcher::OptionalFetchedCategories fetched_categories;
+  EXPECT_CALL(mock_callback(), Run(_))
+      .WillOnce(WithArg<0>(MovePointeeTo(&fetched_categories)));
+
+  NTPSnippetsFetcher::Params params = test_params();
+  params.exclusive_category = OptionalArticlesCategory();
+  snippets_fetcher().FetchSnippets(params, MakeMockCallback());

[tschumann, 2016/11/03 09:20:58]

it would be cleaner to pass-in mock_callback(). Otherwise it's really hard to
follow how mock_callback() should get executed. Maybe the method name is just a
mis-nomer. We should rename it so that it reads like:
ToSnippetsAvailableCallback(mock_callback());

+  FastForwardUntilNoTasksRemain();
+
+  ASSERT_TRUE(fetched_categories);
+  ASSERT_THAT(fetched_categories->size(), Eq(1u));
+  for (const auto& category : *fetched_categories) {

[tschumann, 2016/11/03 09:20:58]

if you already enforce the size of 1, then there's no need for the loop and the
switch. (keep tests simple).

+    const auto& articles = category.snippets;
+    switch (category.category.id()) {
+      case static_cast<int>(KnownCategories::ARTICLES):
+        ASSERT_THAT(articles.size(), Eq(1u));
+        EXPECT_THAT(articles[0]->best_source().url.spec(),
+                    Eq("http://localhost/foobar"));
+        break;
+      default:
+        FAIL() << "unexpected category with ID " << category.category.id();
+    }
+  }
+}
+
 TEST_F(NTPSnippetsFetcherTest, ShouldFetchSuccessfullyEmptyList) {
   const std::string kJsonStr = "{\"recos\": []}";
   SetFakeResponse(/*response_data=*/kJsonStr, net::HTTP_OK,
                   net::URLRequestStatus::SUCCESS);
   EXPECT_CALL(mock_callback(), Run(IsEmptyArticleList()));
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   FastForwardUntilNoTasksRemain();
   EXPECT_THAT(snippets_fetcher().last_status(), Eq("OK"));
   EXPECT_THAT(snippets_fetcher().last_json(), Eq(kJsonStr));
   EXPECT_THAT(
       histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchResult"),
       ElementsAre(base::Bucket(/*min=*/0, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples(
                   "NewTabPage.Snippets.FetchHttpResponseOrErrorCode"),
               ElementsAre(base::Bucket(/*min=*/200, /*count=*/1)));
 }
 
 TEST_F(NTPSnippetsFetcherTest, ShouldRestrictToHosts) {
   net::TestURLFetcherFactory test_url_fetcher_factory;
   NTPSnippetsFetcher::Params params = test_params();
   params.hosts = {"www.somehost1.com", "www.somehost2.com"};
   params.count_to_fetch = 17;
-  snippets_fetcher().FetchSnippets(params);
+  snippets_fetcher().FetchSnippets(params, MakeMockCallback());
   net::TestURLFetcher* fetcher = test_url_fetcher_factory.GetFetcherByID(0);
   ASSERT_THAT(fetcher, NotNull());
   std::unique_ptr<base::Value> value =
       base::JSONReader::Read(fetcher->upload_data());
   ASSERT_TRUE(value) << " failed to parse JSON: "
                      << PrintToString(fetcher->upload_data());
   const base::DictionaryValue* dict = nullptr;
   ASSERT_TRUE(value->GetAsDictionary(&dict));
   const base::DictionaryValue* local_scoring_params = nullptr;
   ASSERT_TRUE(dict->GetDictionary("advanced_options.local_scoring_params",
                                   &local_scoring_params));
   const base::ListValue* content_selectors = nullptr;
   ASSERT_TRUE(
       local_scoring_params->GetList("content_selectors", &content_selectors));
   ASSERT_THAT(content_selectors->GetSize(), Eq(static_cast<size_t>(2)));
   const base::DictionaryValue* content_selector = nullptr;
   ASSERT_TRUE(content_selectors->GetDictionary(0, &content_selector));
   std::string content_selector_value;
   EXPECT_TRUE(content_selector->GetString("value", &content_selector_value));
   EXPECT_THAT(content_selector_value, Eq("www.somehost1.com"));
   ASSERT_TRUE(content_selectors->GetDictionary(1, &content_selector));
   EXPECT_TRUE(content_selector->GetString("value", &content_selector_value));
   EXPECT_THAT(content_selector_value, Eq("www.somehost2.com"));
 }
 
 TEST_F(NTPSnippetsFetcherTest, ShouldReportUrlStatusError) {
   SetFakeResponse(/*response_data=*/std::string(), net::HTTP_NOT_FOUND,
                   net::URLRequestStatus::FAILED);
   EXPECT_CALL(mock_callback(), Run(/*snippets=*/Not(HasValue()))).Times(1);
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   FastForwardUntilNoTasksRemain();
   EXPECT_THAT(snippets_fetcher().last_status(),
               Eq("URLRequestStatus error -2"));
   EXPECT_THAT(snippets_fetcher().last_json(), IsEmpty());
   EXPECT_THAT(
       histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchResult"),
       ElementsAre(base::Bucket(/*min=*/2, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples(
                   "NewTabPage.Snippets.FetchHttpResponseOrErrorCode"),
               ElementsAre(base::Bucket(/*min=*/-2, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchTime"),
               Not(IsEmpty()));
 }
 
 TEST_F(NTPSnippetsFetcherTest, ShouldReportHttpError) {
   SetFakeResponse(/*response_data=*/std::string(), net::HTTP_NOT_FOUND,
                   net::URLRequestStatus::SUCCESS);
   EXPECT_CALL(mock_callback(), Run(/*snippets=*/Not(HasValue()))).Times(1);
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   FastForwardUntilNoTasksRemain();
   EXPECT_THAT(snippets_fetcher().last_json(), IsEmpty());
   EXPECT_THAT(
       histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchResult"),
       ElementsAre(base::Bucket(/*min=*/3, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples(
                   "NewTabPage.Snippets.FetchHttpResponseOrErrorCode"),
               ElementsAre(base::Bucket(/*min=*/404, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchTime"),
               Not(IsEmpty()));
 }
 
 TEST_F(NTPSnippetsFetcherTest, ShouldReportJsonError) {
   const std::string kInvalidJsonStr = "{ \"recos\": []";
   SetFakeResponse(/*response_data=*/kInvalidJsonStr, net::HTTP_OK,
                   net::URLRequestStatus::SUCCESS);
   EXPECT_CALL(mock_callback(), Run(/*snippets=*/Not(HasValue()))).Times(1);
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   FastForwardUntilNoTasksRemain();
   EXPECT_THAT(snippets_fetcher().last_status(),
               StartsWith("Received invalid JSON (error "));
   EXPECT_THAT(snippets_fetcher().last_json(), Eq(kInvalidJsonStr));
   EXPECT_THAT(
       histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchResult"),
       ElementsAre(base::Bucket(/*min=*/4, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples(
                   "NewTabPage.Snippets.FetchHttpResponseOrErrorCode"),
               ElementsAre(base::Bucket(/*min=*/200, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchTime"),
               ElementsAre(base::Bucket(/*min=*/kTestJsonParsingLatencyMs,
                                        /*count=*/1)));
 }
 
 TEST_F(NTPSnippetsFetcherTest, ShouldReportJsonErrorForEmptyResponse) {
   SetFakeResponse(/*response_data=*/std::string(), net::HTTP_OK,
                   net::URLRequestStatus::SUCCESS);
   EXPECT_CALL(mock_callback(), Run(/*snippets=*/Not(HasValue()))).Times(1);
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   FastForwardUntilNoTasksRemain();
   EXPECT_THAT(snippets_fetcher().last_json(), std::string());
   EXPECT_THAT(
       histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchResult"),
       ElementsAre(base::Bucket(/*min=*/4, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples(
                   "NewTabPage.Snippets.FetchHttpResponseOrErrorCode"),
               ElementsAre(base::Bucket(/*min=*/200, /*count=*/1)));
 }
 
 TEST_F(NTPSnippetsFetcherTest, ShouldReportInvalidListError) {
   const std::string kJsonStr =
       "{\"recos\": [{ \"contentInfo\": { \"foo\" : \"bar\" }}]}";
   SetFakeResponse(/*response_data=*/kJsonStr, net::HTTP_OK,
                   net::URLRequestStatus::SUCCESS);
   EXPECT_CALL(mock_callback(), Run(/*snippets=*/Not(HasValue()))).Times(1);
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   FastForwardUntilNoTasksRemain();
   EXPECT_THAT(snippets_fetcher().last_json(), Eq(kJsonStr));
   EXPECT_THAT(
       histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchResult"),
       ElementsAre(base::Bucket(/*min=*/5, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples(
                   "NewTabPage.Snippets.FetchHttpResponseOrErrorCode"),
               ElementsAre(base::Bucket(/*min=*/200, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchTime"),
               Not(IsEmpty()));
 }
 
 // This test actually verifies that the test setup itself is sane, to prevent
 // hard-to-reproduce test failures.
 TEST_F(NTPSnippetsFetcherTest, ShouldReportHttpErrorForMissingBakedResponse) {
   InitFakeURLFetcherFactory();
   EXPECT_CALL(mock_callback(), Run(/*snippets=*/Not(HasValue()))).Times(1);
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   FastForwardUntilNoTasksRemain();
 }
 
 TEST_F(NTPSnippetsFetcherTest, ShouldCancelOngoingFetch) {
   const std::string kJsonStr = "{ \"recos\": [] }";
   SetFakeResponse(/*response_data=*/kJsonStr, net::HTTP_OK,
                   net::URLRequestStatus::SUCCESS);
   EXPECT_CALL(mock_callback(), Run(IsEmptyArticleList()));
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   // Second call to FetchSnippets() overrides/cancels the previous.
   // Callback is expected to be called once.
-  snippets_fetcher().FetchSnippets(test_params());
+  snippets_fetcher().FetchSnippets(test_params(), MakeMockCallback());
   FastForwardUntilNoTasksRemain();
   EXPECT_THAT(
       histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchResult"),
       ElementsAre(base::Bucket(/*min=*/0, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples(
                   "NewTabPage.Snippets.FetchHttpResponseOrErrorCode"),
               ElementsAre(base::Bucket(/*min=*/200, /*count=*/1)));
   EXPECT_THAT(histogram_tester().GetAllSamples("NewTabPage.Snippets.FetchTime"),
               ElementsAre(base::Bucket(/*min=*/kTestJsonParsingLatencyMs,
                                        /*count=*/1)));
 }
 
 ::std::ostream& operator<<(
     ::std::ostream& os,
     const NTPSnippetsFetcher::OptionalFetchedCategories& fetched_categories) {
   if (fetched_categories) {
     // Matchers above aren't any more precise than this, so this is sufficient
     // for test-failure diagnostics.
     return os << "list with " << fetched_categories->size() << " elements";
   }
   return os << "null";
 }
 
 }  // namespace ntp_snippets