Add ContentSuggestionsService tests.

components/ntp_snippets/content_suggestions_service_unittest.cc

Index: components/ntp_snippets/content_suggestions_service_unittest.cc
diff --git a/components/ntp_snippets/content_suggestions_service_unittest.cc b/components/ntp_snippets/content_suggestions_service_unittest.cc
index 91fd665dc6e7b6cf6643b9adf27a4afe29b6f8af..d80d8206ca63891cdfd70fce49ba6279e6c2b977 100644
--- a/components/ntp_snippets/content_suggestions_service_unittest.cc
+++ b/components/ntp_snippets/content_suggestions_service_unittest.cc
@@ -58,8 +58,13 @@ class MockProvider : public ContentSuggestionsProvider {
   MockProvider(Observer* observer,
                CategoryFactory* category_factory,
                std::vector<Category> provided_categories)
-      : ContentSuggestionsProvider(observer, category_factory),
-        provided_categories_(provided_categories) {
+      : ContentSuggestionsProvider(observer, category_factory) {
+    SetProvidedCategories(provided_categories);
+  }
+
+  void SetProvidedCategories(std::vector<Category> provided_categories) {
+    statuses_.clear();
+    provided_categories_ = provided_categories;
     for (Category category : provided_categories) {
       statuses_[category.id()] = CategoryStatus::AVAILABLE;
     }
@@ -363,4 +368,74 @@ TEST_F(ContentSuggestionsServiceTest, ShouldForwardSuggestions) {
   // The service will receive two Shutdown() calls.
 }
 
+TEST_F(ContentSuggestionsServiceTest,
+       ShouldNotReturnCategoryInfoForNonexistentCategory) {
+  Category category = FromKnownCategory(KnownCategories::BOOKMARKS);
+  base::Optional<CategoryInfo> result = service()->GetCategoryInfo(category);
+  EXPECT_FALSE(result.has_value());
+}
+
+TEST_F(ContentSuggestionsServiceTest, ShouldReturnCategoryInfo) {
+  Category category = FromKnownCategory(KnownCategories::BOOKMARKS);
+  MockProvider* provider = MakeProvider(category);
+  base::Optional<CategoryInfo> result = service()->GetCategoryInfo(category);
+  EXPECT_TRUE(result.has_value());
+  CategoryInfo expected = provider->GetCategoryInfo(category);
+  const CategoryInfo& actual = result.value();
+  EXPECT_EQ(expected.title(), actual.title());
+  EXPECT_EQ(expected.card_layout(), actual.card_layout());
+  EXPECT_EQ(expected.has_more_button(), actual.has_more_button());
+}
+
+TEST_F(ContentSuggestionsServiceTest,
+       ShouldRegisterNewCategoryOnNewSuggestions) {

[Philipp Keck, 2016/08/18 12:51:58]

OnCategoryStatusChanged has the same ability of adding a category that didn't
exist before. Testing that when the status becomes AVAILABLE is trivial, it's
the same as this test case here, so we probably won't need another one. But
there is the case where a category comes into existence without becoming
AVAILABLE.
So maybe could add a ShouldRegisterNewCategoryOnCategoryStatusChanged and use
SIGNED_OUT or INITIALIZING there.

[vitaliii, 2016/08/18 13:12:35]

Done.

+  Category category = FromKnownCategory(KnownCategories::BOOKMARKS);
+  MockProvider* provider = MakeProvider(category);
+  MockServiceObserver observer;
+  service()->AddObserver(&observer);
+
+  // Provider starts providing |new_category| without calling
+  // |OnCategoryStatusChanged|.
+  Category new_category = FromKnownCategory(KnownCategories::ARTICLES);
+  provider->SetProvidedCategories(
+      std::vector<Category>({category, new_category}));
+
+  EXPECT_CALL(observer, OnNewSuggestions(new_category)).Times(1);
+  EXPECT_CALL(observer,
+              OnCategoryStatusChanged(new_category, CategoryStatus::AVAILABLE))
+      .Times(1);
+  provider->FireSuggestionsChanged(new_category, {1, 2});
+
+  ExpectThatSuggestionsAre(new_category, {1, 2});
+  EXPECT_THAT(providers().at(category), Eq(provider));
+  EXPECT_THAT(service()->GetCategoryStatus(category),
+              Eq(CategoryStatus::AVAILABLE));
+  EXPECT_THAT(providers().at(new_category), Eq(provider));
+  EXPECT_THAT(service()->GetCategoryStatus(new_category),
+              Eq(CategoryStatus::AVAILABLE));
+
+  service()->RemoveObserver(&observer);
+}
+
+TEST_F(ContentSuggestionsServiceTest, ShouldRemoveCategoryWhenNotProvided) {
+  Category category = FromKnownCategory(KnownCategories::BOOKMARKS);
+  MockProvider* provider = MakeProvider(category);
+  MockServiceObserver observer;
+  service()->AddObserver(&observer);
+
+  provider->FireSuggestionsChanged(category, {1, 2});
+  ExpectThatSuggestionsAre(category, {1, 2});
+
+  EXPECT_CALL(observer,
+              OnCategoryStatusChanged(category, CategoryStatus::NOT_PROVIDED));
+  provider->FireCategoryStatusChanged(category, CategoryStatus::NOT_PROVIDED);
+
+  EXPECT_THAT(service()->GetCategoryStatus(category),
+              Eq(CategoryStatus::NOT_PROVIDED));
+  EXPECT_TRUE(service()->GetCategories().empty());
+  ExpectThatSuggestionsAre(category, std::vector<int>());
+
+  service()->RemoveObserver(&observer);
+}
+
 }  // namespace ntp_snippets