Add a way to reconfigure cell from IndexPaths

ios/chrome/browser/ui/collection_view/collection_view_controller_unittest.mm

Index: ios/chrome/browser/ui/collection_view/collection_view_controller_unittest.mm
diff --git a/ios/chrome/browser/ui/collection_view/collection_view_controller_unittest.mm b/ios/chrome/browser/ui/collection_view/collection_view_controller_unittest.mm
index d2318fb8c83e5c3d466e448901c863b5bcd53aa3..aaaeeb9175a19f12ce0a38fccd0f69043e1e764b 100644
--- a/ios/chrome/browser/ui/collection_view/collection_view_controller_unittest.mm
+++ b/ios/chrome/browser/ui/collection_view/collection_view_controller_unittest.mm
@@ -44,7 +44,73 @@ typedef NS_ENUM(NSInteger, ItemType) {
   ItemTypeFooBiz,
 };
 
-class CollectionViewControllerTest : public BlockCleanupTest {};
+typedef void (^ReconfigureBlock)(CollectionViewController*,
+                                 NSArray*,
+                                 SectionIdentifier);
+
+class CollectionViewControllerTest : public BlockCleanupTest {
+ public:
+  void TestReconfigureBlock(ReconfigureBlock block) {
+    // Setup.
+    CollectionViewController* controller = [[CollectionViewController alloc]
+        initWithStyle:CollectionViewControllerStyleDefault];
+    [controller loadModel];
+
+    CollectionViewModel* model = [controller collectionViewModel];
+    [model addSectionWithIdentifier:SectionIdentifierFoo];
+
+    MockCollectionViewItem* firstReconfiguredItem =
+        [[MockCollectionViewItem alloc] initWithType:ItemTypeFooBar];
+    [model addItem:firstReconfiguredItem
+        toSectionWithIdentifier:SectionIdentifierFoo];
+
+    MockCollectionViewItem* secondReconfiguredItem =
+        [[MockCollectionViewItem alloc] initWithType:ItemTypeFooBiz];
+    [model addItem:secondReconfiguredItem
+        toSectionWithIdentifier:SectionIdentifierFoo];
+
+    MockCollectionViewItem* firstNonReconfiguredItem =
+        [[MockCollectionViewItem alloc] initWithType:ItemTypeFooBiz];
+    [model addItem:firstNonReconfiguredItem
+        toSectionWithIdentifier:SectionIdentifierFoo];
+
+    MockCollectionViewItem* thirdReconfiguredItem =
+        [[MockCollectionViewItem alloc] initWithType:ItemTypeFooBiz];
+    [model addItem:thirdReconfiguredItem
+        toSectionWithIdentifier:SectionIdentifierFoo];
+
+    MockCollectionViewItem* secondNonReconfiguredItem =
+        [[MockCollectionViewItem alloc] initWithType:ItemTypeFooBiz];
+    [model addItem:secondNonReconfiguredItem
+        toSectionWithIdentifier:SectionIdentifierFoo];
+
+    // The collection view is not visible on screen, so it has not created any
+    // of its cells.  Swizzle |cellsForItemAtIndexPath:| and inject an
+    // implementation for testing that always returns a non-nil cell.
+    MDCCollectionViewCell* dummyCell = [[MDCCollectionViewCell alloc] init];
+    {
+      ScopedBlockSwizzler swizzler([UICollectionView class],
+                                   @selector(cellForItemAtIndexPath:),
+                                   ^(id self) {
+                                     return dummyCell;
+                                   });
+
+      NSArray* itemsToReconfigure = @[
+        firstReconfiguredItem, secondReconfiguredItem, thirdReconfiguredItem
+      ];
+      // Action.
+      block(controller, itemsToReconfigure, SectionIdentifierFoo);
+    }
+
+    // Tests.
+    EXPECT_TRUE([firstReconfiguredItem configureCellCalled]);
+    EXPECT_TRUE([secondReconfiguredItem configureCellCalled]);
+    EXPECT_TRUE([thirdReconfiguredItem configureCellCalled]);
+
+    EXPECT_FALSE([firstNonReconfiguredItem configureCellCalled]);
+    EXPECT_FALSE([secondNonReconfiguredItem configureCellCalled]);
+  }
+};
 
 }  // namespace
 
@@ -79,60 +145,30 @@ TEST_F(CollectionViewControllerTest, CellForItemAtIndexPath) {
 }
 
 TEST_F(CollectionViewControllerTest, ReconfigureCells) {
-  CollectionViewController* controller = [[CollectionViewController alloc]
-      initWithStyle:CollectionViewControllerStyleDefault];
-  [controller loadModel];
-
-  CollectionViewModel* model = [controller collectionViewModel];
-  [model addSectionWithIdentifier:SectionIdentifierFoo];
-
-  MockCollectionViewItem* firstReconfiguredItem =
-      [[MockCollectionViewItem alloc] initWithType:ItemTypeFooBar];
-  [model addItem:firstReconfiguredItem
-      toSectionWithIdentifier:SectionIdentifierFoo];
-
-  MockCollectionViewItem* secondReconfiguredItem =
-      [[MockCollectionViewItem alloc] initWithType:ItemTypeFooBiz];
-  [model addItem:secondReconfiguredItem
-      toSectionWithIdentifier:SectionIdentifierFoo];
-
-  MockCollectionViewItem* firstNonReconfiguredItem =
-      [[MockCollectionViewItem alloc] initWithType:ItemTypeFooBiz];
-  [model addItem:firstNonReconfiguredItem
-      toSectionWithIdentifier:SectionIdentifierFoo];
-
-  MockCollectionViewItem* thirdReconfiguredItem =
-      [[MockCollectionViewItem alloc] initWithType:ItemTypeFooBiz];
-  [model addItem:thirdReconfiguredItem
-      toSectionWithIdentifier:SectionIdentifierFoo];
-
-  MockCollectionViewItem* secondNonReconfiguredItem =
-      [[MockCollectionViewItem alloc] initWithType:ItemTypeFooBiz];
-  [model addItem:secondNonReconfiguredItem
-      toSectionWithIdentifier:SectionIdentifierFoo];
-
-  // The collection view is not visible on screen, so it has not created any of
-  // its cells.  Swizzle |cellsForItemAtIndexPath:| and inject an implementation
-  // for testing that always returns a non-nil cell.
-  MDCCollectionViewCell* dummyCell = [[MDCCollectionViewCell alloc] init];
-  {
-    ScopedBlockSwizzler swizzler([UICollectionView class],
-                                 @selector(cellForItemAtIndexPath:),
-                                 ^(id self) {
-                                   return dummyCell;
-                                 });
-
-    NSArray* itemsToReconfigure = @[
-      firstReconfiguredItem, secondReconfiguredItem, thirdReconfiguredItem
-    ];
+  TestReconfigureBlock(^void(CollectionViewController* controller,
+                             NSArray* itemsToReconfigure,
+                             SectionIdentifier sectionIdentifier) {
     [controller reconfigureCellsForItems:itemsToReconfigure
-                 inSectionWithIdentifier:SectionIdentifierFoo];
-  }
-
-  EXPECT_TRUE([firstReconfiguredItem configureCellCalled]);
-  EXPECT_TRUE([secondReconfiguredItem configureCellCalled]);
-  EXPECT_TRUE([thirdReconfiguredItem configureCellCalled]);
+                 inSectionWithIdentifier:sectionIdentifier];
+  });
+}
 
-  EXPECT_FALSE([firstNonReconfiguredItem configureCellCalled]);
-  EXPECT_FALSE([secondNonReconfiguredItem configureCellCalled]);
+TEST_F(CollectionViewControllerTest, ReconfigureCellsWithIndexPath) {
+  TestReconfigureBlock(^void(CollectionViewController* controller,
+                             NSArray* itemsToReconfigure,
+                             SectionIdentifier sectionIdentifier) {
+    // More setup.
+    NSMutableArray* indexPaths = [NSMutableArray array];
+    for (CollectionViewItem* item : itemsToReconfigure) {
+      NSIndexPath* indexPath =
+          [controller.collectionViewModel indexPathForItem:item
+                                   inSectionWithIdentifier:sectionIdentifier];
+      if (indexPath) {
+        [indexPaths addObject:indexPath];
+      }
+    }
+
+    // Action.
+    [controller reconfigureCellsAtIndexPaths:indexPaths];
+  });
 }