Add edge-case unit tests

Summary:
- Removed dead code in batch data and updater
- Tested updating with empty index sets
- Tested updating with not-found section controller
- Tested reloading when collection view or data source are not set
- Tested `-[IGListAdapter sectionForObject:]`
- Tested index path return for not-found section controller
- Tested pointer comparison with `NSObject+IGListDiffable` category

Fixes #190, #189

- [x] All tests pass. Demo project builds and runs.
- [x] I added tests, an experiment, or detailed why my change isn't tested.
- [x] I have reviewed the [contributing guide](https://github.com/Instagram/IGListKit/blob/master/CONTRIBUTING.md)
Closes https://github.com/Instagram/IGListKit/pull/191

Differential Revision: D4172781

Pulled By: rnystrom

fbshipit-source-id: c25cc917e9a1ebc5fc94fa022e01f99c80c2466c

Source/IGListAdapterUpdater.m

@@ -221,17 +221,6 @@ static NSArray *objectsWithDuplicateIdentifiersRemoved(NSArray<id<IGListDiffable
     }
 }
 
-- (NSSet *)filterIndexPaths:(NSSet<NSIndexPath *> *)indexPaths removingSections:(NSIndexSet *)sections {
-    NSMutableSet *filteredIndexPaths = [indexPaths mutableCopy];
-    for (NSIndexPath *indexPath in indexPaths) {
-        const NSUInteger section = indexPath.section;
-        if ([sections containsIndex:section]) {
-            [filteredIndexPaths removeObject:indexPath];
-        }
-    }
-    return filteredIndexPaths;
-}
-
 void convertReloadToDeleteInsert(NSMutableIndexSet *reloads,
                                  NSMutableIndexSet *deletes,
                                  NSMutableIndexSet *inserts,
@@ -300,16 +289,6 @@ void convertReloadToDeleteInsert(NSMutableIndexSet *reloads,
     self.batchUpdateOrReloadInProgress = NO;
 }
 
-- (NSArray *)trimmedIndexPaths:(NSArray <NSIndexPath *> *)indexPaths inSections:(NSIndexSet *)sections {
-    NSMutableArray *paths = [indexPaths mutableCopy];
-    for (NSInteger i = 0; i < paths.count; i++) {
-        if ([sections containsIndex:[paths[i] section]]) {
-            [paths removeObjectAtIndex:i];
-        }
-    }
-    return paths;
-}
-
 - (void)cleanupState {
     self.queuedUpdateIsAnimated = YES;
 

Source/IGListBatchUpdateData.mm

@@ -40,21 +40,6 @@ static void convertMoveToDeleteAndInsert(NSMutableSet<IGListMoveIndex *> *moves,
 
 @implementation IGListBatchUpdateData
 
-// Converts all moves that have section operations into a section delete + insert.
-+ (void)cleanIndexSetWithMap:(const std::unordered_map<NSUInteger, IGListMoveIndex*> &)map
-                       moves:(NSMutableSet<IGListMoveIndex *> *)moves
-                    sections:(NSMutableIndexSet *)sections
-                     deletes:(NSMutableIndexSet *)deletes
-                     inserts:(NSMutableIndexSet *)inserts {
-    for(const auto &i : map) {
-        const NSUInteger index = i.first;
-        if ([sections containsIndex:index]) {
-            [sections removeIndex:index];
-            convertMoveToDeleteAndInsert(moves, i.second, deletes, inserts);
-        }
-    }
-}
-
 // Converts all section moves that have index path operations into a section delete + insert.
 + (void)cleanIndexPathsWithMap:(const std::unordered_map<NSUInteger, IGListMoveIndex*> &)map
                          moves:(NSMutableSet<IGListMoveIndex *> *)moves

Source/Internal/IGListAdapterInternal.h

@@ -32,7 +32,8 @@ IGListCollectionContext
     __weak UICollectionView *_collectionView;
 }
 
-@property (nonatomic, strong, readonly) id <IGListUpdatingDelegate> updatingDelegate;
+@property (nonatomic, strong) id <IGListUpdatingDelegate> updatingDelegate;
+
 @property (nonatomic, strong, readonly) IGListSectionMap *sectionMap;
 @property (nonatomic, strong, readonly) IGListDisplayHandler *displayHandler;
 @property (nonatomic, strong, readonly) IGListWorkingRangeHandler *workingRangeHandler;
@@ -61,6 +62,7 @@ IGListCollectionContext
 - (NSArray *)indexPathsFromSectionController:(IGListSectionController <IGListSectionType> *)sectionController
                                      indexes:(NSIndexSet *)indexes
                         adjustForUpdateBlock:(BOOL)adjustForUpdateBlock;
+- (NSIndexPath *)indexPathForSectionController:(IGListSectionController *)controller index:(NSInteger)index;
 
 @end
 

Tests/IGListAdapterTests.m

@@ -13,7 +13,6 @@
 #import <OCMock/OCMock.h>
 
 #import <IGListKit/IGListKit.h>
-#import <IGListKit/IGListReloadDataUpdater.h>
 
 #import "IGListAdapterInternal.h"
 #import "IGListTestAdapterDataSource.h"
@@ -626,4 +625,107 @@ XCTAssertEqual(CGPointEqualToPoint(point, p), YES); \
     IGAssertEqualPoint([self.collectionView contentOffset], 0, 10);
 }
 
+- (void)test_whenQueryingIndexPath_withOOBSectionController_thatNilReturned {
+    self.dataSource.objects = @[@0, @1, @2];
+    [self.adapter reloadDataWithCompletion:nil];
+
+    id randomSectionController = [IGListSectionController new];
+    XCTAssertNil([self.adapter indexPathForSectionController:randomSectionController index:0]);
+}
+
+- (void)test_whenQueryingSectionForObject_thatSectionReturned {
+    self.dataSource.objects = @[@0, @1, @2];
+    [self.adapter reloadDataWithCompletion:nil];
+    XCTAssertEqual([self.adapter sectionForObject:@0], 0);
+    XCTAssertEqual([self.adapter sectionForObject:@1], 1);
+    XCTAssertEqual([self.adapter sectionForObject:@2], 2);
+    XCTAssertEqual([self.adapter sectionForObject:@3], NSNotFound);
+}
+
+- (void)test_whenReloadingData_withNoDataSource_thatCompletionCalledWithNO {
+    self.dataSource.objects = @[@1];
+    IGListAdapter *adapter = [[IGListAdapter alloc] initWithUpdater:[IGListReloadDataUpdater new]
+                                                     viewController:nil
+                                                   workingRangeSize:0];
+    adapter.collectionView = self.collectionView;
+
+    __block BOOL executed = NO;
+    [adapter reloadDataWithCompletion:^(BOOL finished) {
+        executed = YES;
+        XCTAssertFalse(finished);
+    }];
+    XCTAssertTrue(executed);
+}
+
+- (void)test_whenReloadingData_withNoCollectionView_thatCompletionCalledWithNO {
+    self.dataSource.objects = @[@1];
+    IGListAdapter *adapter = [[IGListAdapter alloc] initWithUpdater:[IGListReloadDataUpdater new]
+                                                     viewController:nil
+                                                   workingRangeSize:0];
+    adapter.dataSource = self.dataSource;
+
+    __block BOOL executed = NO;
+    [adapter reloadDataWithCompletion:^(BOOL finished) {
+        executed = YES;
+        XCTAssertFalse(finished);
+    }];
+    XCTAssertTrue(executed);
+}
+
+- (void)test_whenSectionControllerReloading_withEmptyIndexes_thatNoUpdatesHappen {
+    self.dataSource.objects = @[@0, @1, @2];
+    [self.adapter reloadDataWithCompletion:nil];
+
+    id mockDelegate = [OCMockObject mockForProtocol:@protocol(IGListUpdatingDelegate)];
+    [[mockDelegate reject] reloadItemsInCollectionView:[OCMArg any] indexPaths:[OCMArg any]];
+    self.adapter.updatingDelegate = mockDelegate;
+
+    id sectionController = [self.adapter sectionControllerForObject:@1];
+    [self.adapter reloadInSectionController:sectionController atIndexes:[NSIndexSet new]];
+
+    [mockDelegate verify];
+}
+
+- (void)test_whenSectionControllerDeleting_withEmptyIndexes_thatNoUpdatesHappen {
+    self.dataSource.objects = @[@0, @1, @2];
+    [self.adapter reloadDataWithCompletion:nil];
+
+    id mockDelegate = [OCMockObject mockForProtocol:@protocol(IGListUpdatingDelegate)];
+    [[mockDelegate reject] deleteItemsFromCollectionView:[OCMArg any] indexPaths:[OCMArg any]];
+    self.adapter.updatingDelegate = mockDelegate;
+
+    id sectionController = [self.adapter sectionControllerForObject:@1];
+    [self.adapter deleteInSectionController:sectionController atIndexes:[NSIndexSet new]];
+
+    [mockDelegate verify];
+}
+
+- (void)test_whenSectionControllerInserting_withEmptyIndexes_thatNoUpdatesHappen {
+    self.dataSource.objects = @[@0, @1, @2];
+    [self.adapter reloadDataWithCompletion:nil];
+
+    id mockDelegate = [OCMockObject mockForProtocol:@protocol(IGListUpdatingDelegate)];
+    [[mockDelegate reject] insertItemsIntoCollectionView:[OCMArg any] indexPaths:[OCMArg any]];
+    self.adapter.updatingDelegate = mockDelegate;
+
+    id sectionController = [self.adapter sectionControllerForObject:@1];
+    [self.adapter insertInSectionController:sectionController atIndexes:[NSIndexSet new]];
+
+    [mockDelegate verify];
+}
+
+- (void)test_whenReloading_withSectionControllerNotFound_thatNoUpdatesHappen {
+    self.dataSource.objects = @[@0, @1, @2];
+    [self.adapter reloadDataWithCompletion:nil];
+
+    id mockDelegate = [OCMockObject mockForProtocol:@protocol(IGListUpdatingDelegate)];
+    [[mockDelegate reject] reloadCollectionView:[OCMArg any] sections:[OCMArg any]];
+    self.adapter.updatingDelegate = mockDelegate;
+
+    id sectionController = [IGListSectionController new];
+    [self.adapter reloadSectionController:sectionController];
+
+    [mockDelegate verify];
+}
+
 @end

Tests/IGListDiffTests.m

@@ -428,4 +428,9 @@ static NSArray *sorted(NSArray *arr) {
     XCTAssertEqualObjects(sorted(result.inserts), expectedInserts);
 }
 
+- (void)test_whenComparingDiffableObjects_withDefaultCategory_thatPointersAreAlwaysEqual {
+    NSObject *object = [NSObject new];
+    XCTAssertTrue([object isEqualToDiffableObject:object]);
+}
+
 @end