Add a message to empty ContentSuggestions sections

ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater_unittest.mm

Index: ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater_unittest.mm
diff --git a/ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater_unittest.mm b/ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater_unittest.mm
new file mode 100644
index 0000000000000000000000000000000000000000..71956f28b73cc4463d64d9facb3f242418c06f8d
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+++ b/ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater_unittest.mm
@@ -0,0 +1,75 @@
+// 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.
+
+#import "ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater.h"
+
+#import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
+#import "ios/chrome/browser/ui/content_suggestions/content_suggestion.h"
+#import "ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller.h"
+#import "ios/chrome/browser/ui/content_suggestions/identifier/content_suggestion_identifier.h"
+#import "ios/chrome/browser/ui/content_suggestions/identifier/content_suggestions_section_information.h"
+#include "testing/platform_test.h"
+#import "third_party/ocmock/OCMock/OCMock.h"
+#import "third_party/ocmock/gtest_support.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace {
+
+TEST(ContentSuggestionsCollectionUpdaterTest, addEmptyItemToEmptySection) {
+  // Setup.
+  ContentSuggestionsCollectionUpdater* updater =
+      [[ContentSuggestionsCollectionUpdater alloc] initWithDataSource:nil];
+  CollectionViewModel* model = [[CollectionViewModel alloc] init];
+  id mockCollection = OCMClassMock([ContentSuggestionsViewController class]);
+  OCMStub([mockCollection collectionViewModel]).andReturn(model);
+  updater.collectionViewController = mockCollection;
+
+  ContentSuggestion* suggestion = [[ContentSuggestion alloc] init];
+  suggestion.suggestionIdentifier = [[ContentSuggestionIdentifier alloc] init];
+  suggestion.suggestionIdentifier.sectionInfo =
+      [[ContentSuggestionsSectionInformation alloc]
+          initWithSectionID:ContentSuggestionsSectionArticles];
+  suggestion.suggestionIdentifier.sectionInfo.showIfEmpty = YES;
+  [updater addSectionsForSuggestionsToModel:@[ suggestion ]];
+  ASSERT_EQ(0, [model numberOfItemsInSection:0]);
+
+  // Action.
+  NSIndexPath* addedItem = [updater addEmptyItemForSection:0];
+
+  // Test.
+  EXPECT_TRUE([[NSIndexPath indexPathForItem:0 inSection:0] isEqual:addedItem]);
+  ASSERT_EQ(1, [model numberOfItemsInSection:0]);
+}
+
+TEST(ContentSuggestionsCollectionUpdaterTest, addEmptyItemToSection) {
+  // Setup.
+  ContentSuggestionsCollectionUpdater* updater =
+      [[ContentSuggestionsCollectionUpdater alloc] initWithDataSource:nil];
+  CollectionViewModel* model = [[CollectionViewModel alloc] init];
+  id mockCollection = OCMClassMock([ContentSuggestionsViewController class]);
+  OCMStub([mockCollection collectionViewModel]).andReturn(model);
+  updater.collectionViewController = mockCollection;
+
+  ContentSuggestion* suggestion = [[ContentSuggestion alloc] init];
+  suggestion.suggestionIdentifier = [[ContentSuggestionIdentifier alloc] init];
+  suggestion.suggestionIdentifier.sectionInfo =
+      [[ContentSuggestionsSectionInformation alloc]
+          initWithSectionID:ContentSuggestionsSectionArticles];
+  suggestion.suggestionIdentifier.sectionInfo.showIfEmpty = YES;
+  [updater addSectionsForSuggestionsToModel:@[ suggestion ]];
+  [updater addSuggestionsToModel:@[ suggestion ]];
+  ASSERT_EQ(1, [model numberOfItemsInSection:0]);
+
+  // Action.
+  NSIndexPath* addedItem = [updater addEmptyItemForSection:0];
+
+  // Test.
+  EXPECT_TRUE([[NSIndexPath indexPathForItem:1 inSection:0] isEqual:addedItem]);
+  ASSERT_EQ(2, [model numberOfItemsInSection:0]);
+}
+
+}  // namespace