[Offline Pages] Set up the initial prefetching service.

chrome/browser/android/offline_pages/offline_page_suggestions_observer_unittest.cc

+// Copyright 2017 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 "chrome/browser/android/offline_pages/offline_page_suggestions_observer.h"
+
+#include "base/run_loop.h"
+#include "base/test/test_simple_task_runner.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "chrome/test/base/testing_profile.h"
+#include "components/offline_pages/core/stub_offline_page_model.h"
+#include "content/public/test/test_browser_thread_bundle.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "url/gurl.h"
+
+namespace offline_pages {
+
+namespace {
+
+class TestingPrefetchService : public PrefetchService {
+ public:
+  TestingPrefetchService() = default;
+
+  void OnNewURLsToPrefetch(std::vector<GURL> suggested_urls) override {
+    latest_url_suggestions = suggested_urls;
+    new_suggestions_count++;
+  }
+  void RemoveAllUnprocessedURLsToPrefetch() override {
+    latest_url_suggestions.clear();
+    remove_all_suggestions_count++;
+  }
+
+  std::vector<GURL> latest_url_suggestions;
+  int new_suggestions_count = 0;
+  int remove_all_suggestions_count = 0;
+};
+
+class TestDelegate : public SuggestionsObserver::Delegate {
+ public:
+  TestDelegate() = default;
+  ~TestDelegate() override = default;
+
+  std::vector<GURL> GetSuggestionURLs(
+      const ntp_snippets::Category& category) override {
+    get_suggestion_urls_count++;
+    return suggestion_urls;
+  }
+
+  PrefetchService* GetPrefetchService(
+      content::BrowserContext* context) override {
+    return &prefetch_service;
+  }
+
+  TestingPrefetchService prefetch_service;
+
+  // Public for test manipulation.
+  std::vector<GURL> suggestion_urls;
+
+  // Signals that delegate was called.
+  int get_suggestion_urls_count = 0;
+};
+
+}  // namespace
+
+class OfflinePageSuggestionsObserverTest : public testing::Test {
+ public:
+  OfflinePageSuggestionsObserverTest() = default;
+
+  void SetUp() override {
+    observer_ = base::MakeUnique<SuggestionsObserver>(&profile_, MakeDelegate(),
+                                                      category);
+  }
+
+  virtual std::unique_ptr<SuggestionsObserver::Delegate> MakeDelegate() {
+    auto delegate_ptr = base::MakeUnique<TestDelegate>();
+    test_delegate_ = delegate_ptr.get();
+    return std::move(delegate_ptr);
+  }
+
+  SuggestionsObserver* observer() { return observer_.get(); }
+
+  TestDelegate* test_delegate() { return test_delegate_; }
+  TestingPrefetchService* test_prefetch_service() {
+    return &(test_delegate()->prefetch_service);
+  }
+
+ protected:
+  ntp_snippets::Category category = ntp_snippets::Category::FromKnownCategory(
+      ntp_snippets::KnownCategories::ARTICLES);
+  content::TestBrowserThreadBundle thread_bundle_;
+  TestingProfile profile_;
+
+ private:
+  std::unique_ptr<SuggestionsObserver> observer_;
+  TestDelegate* test_delegate_;
+};
+
+TEST_F(OfflinePageSuggestionsObserverTest, CallsDelegateOnNewSuggestions) {
+  // We should not do anything if the category is not loaded.
+  observer()->OnNewSuggestions(category);
+  EXPECT_EQ(0, test_delegate()->get_suggestion_urls_count);
+  EXPECT_EQ(0, test_prefetch_service()->new_suggestions_count);
+
+  // Once the category becomes available, new suggestions should cause us to ask
+  // the delegate for suggestion URLs.
+  observer()->OnCategoryStatusChanged(category,
+                                      ntp_snippets::CategoryStatus::AVAILABLE);
+  observer()->OnNewSuggestions(category);
+  EXPECT_EQ(1, test_delegate()->get_suggestion_urls_count);
+
+  // We expect that no pages were forwarded to the prefetch service since no
+  // pages were prepopulated.
+  EXPECT_EQ(0, test_prefetch_service()->new_suggestions_count);
+}
+
+TEST_F(OfflinePageSuggestionsObserverTest,
+       ForwardsSuggestionsToPrefetchService) {
+  const GURL test_url_1("https://www.example.com/1");
+  test_delegate()->suggestion_urls.push_back(test_url_1);
+
+  observer()->OnCategoryStatusChanged(category,
+                                      ntp_snippets::CategoryStatus::AVAILABLE);
+  observer()->OnNewSuggestions(category);
+  EXPECT_EQ(1, test_prefetch_service()->new_suggestions_count);
+  EXPECT_EQ(1U, test_prefetch_service()->latest_url_suggestions.size());
+  EXPECT_EQ(test_url_1, test_prefetch_service()->latest_url_suggestions[0]);
+}
+
+TEST_F(OfflinePageSuggestionsObserverTest, RemovesAllOnBadStatus) {
+  const GURL test_url_1("https://www.example.com/1");
+  const GURL test_url_2("https://www.example.com/2");
+  test_delegate()->suggestion_urls.push_back(test_url_1);
+  test_delegate()->suggestion_urls.push_back(test_url_2);
+
+  observer()->OnCategoryStatusChanged(category,
+                                      ntp_snippets::CategoryStatus::AVAILABLE);
+  observer()->OnNewSuggestions(category);
+  ASSERT_EQ(2U, test_prefetch_service()->latest_url_suggestions.size());
+
+  observer()->OnCategoryStatusChanged(
+      category, ntp_snippets::CategoryStatus::CATEGORY_EXPLICITLY_DISABLED);
+  ASSERT_EQ(1, test_prefetch_service()->remove_all_suggestions_count);
+  observer()->OnCategoryStatusChanged(
+      category,
+      ntp_snippets::CategoryStatus::ALL_SUGGESTIONS_EXPLICITLY_DISABLED);
+  ASSERT_EQ(2, test_prefetch_service()->remove_all_suggestions_count);
+}
+
+}  // namespace offline_pages