Add a unit test for the BookmarkSuggestionsProvider.

components/ntp_snippets/fake_content_suggestions_provider_observer.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 "components/ntp_snippets/fake_content_suggestions_provider_observer.h"
+
+#include <utility>
+
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace ntp_snippets {
+
+using testing::Eq;
+using testing::Not;
+
+FakeContentSuggestionsProviderObserver::
+    FakeContentSuggestionsProviderObserver() = default;
+
+FakeContentSuggestionsProviderObserver::
+    ~FakeContentSuggestionsProviderObserver() = default;
+
+void FakeContentSuggestionsProviderObserver::OnNewSuggestions(
+    ContentSuggestionsProvider* provider,
+    Category category,
+    std::vector<ContentSuggestion> suggestions) {
+  suggestions_[category] = std::move(suggestions);
+}
+
+void FakeContentSuggestionsProviderObserver::OnCategoryStatusChanged(
+    ContentSuggestionsProvider* provider,
+    Category category,
+    CategoryStatus new_status) {
+  statuses_[category] = new_status;
+}
+
+void FakeContentSuggestionsProviderObserver::OnSuggestionInvalidated(
+    ContentSuggestionsProvider* provider,
+    const ContentSuggestion::ID& suggestion_id) {
+  FAIL() << "not implemented.";
+}
+
+const std::map<Category, CategoryStatus, Category::CompareByID>&
+FakeContentSuggestionsProviderObserver::statuses() const {
+  return statuses_;
+}
+
+CategoryStatus FakeContentSuggestionsProviderObserver::StatusForCategory(
+    Category category) const {
+  auto it = statuses_.find(category);
+  EXPECT_THAT(it, Not(Eq(statuses_.end())));
+  return it->second;
+}
+
+const std::vector<ContentSuggestion>&
+FakeContentSuggestionsProviderObserver::SuggestionsForCategory(
+    Category category) {
+  return suggestions_[category];
+}
+
+}  // namespace ntp_snippets