Bring Test Coverage back to > 99%

Examples/Examples-iOS/IGListKitExamples-UITests/DemosViewControllerUITests.swift

@@ -97,10 +97,10 @@ final class DemosViewControllerUITests: UITestCase {
         let exactBar    = app.navigationBars[title]
         let compactBar  = app.navigationBars[title.replacingOccurrences(of: " ", with: "")]
 
-        waitToAppear(element: exactBar, timeout: 2)
+        waitToAppear(element: exactBar, timeout: 5)
 
         if !exactBar.exists {
-            waitToAppear(element: compactBar, timeout: 2)
+            waitToAppear(element: compactBar, timeout: 5)
         }
 
         XCTAssertTrue(

IGListKit.xcodeproj/project.pbxproj

@@ -28,6 +28,16 @@
 		16B71CEE22B0A08400FE96ED /* IGTestInvalidateLayoutDataSource.m in Sources */ = {isa = PBXBuildFile; fileRef = 16B71CE822B0A08300FE96ED /* IGTestInvalidateLayoutDataSource.m */; };
 		16B71CEF22B0A08400FE96ED /* IGTestInvalidateLayoutObject.m in Sources */ = {isa = PBXBuildFile; fileRef = 16B71CEA22B0A08300FE96ED /* IGTestInvalidateLayoutObject.m */; };
 		16B71CF022B0A08400FE96ED /* IGTestInvalidateLayoutObject.m in Sources */ = {isa = PBXBuildFile; fileRef = 16B71CEA22B0A08300FE96ED /* IGTestInvalidateLayoutObject.m */; };
+		22907ABD2F2862830015F3D0 /* IGListViewVisibilityTrackerTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 22907ABC2F2862830015F3D0 /* IGListViewVisibilityTrackerTests.m */; };
+		22907ABE2F2862830015F3D0 /* IGListViewVisibilityTrackerTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 22907ABC2F2862830015F3D0 /* IGListViewVisibilityTrackerTests.m */; };
+		22907AC12F2864450015F3D0 /* IGListItemUpdatesCollectorTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 22907AC02F2864450015F3D0 /* IGListItemUpdatesCollectorTests.m */; };
+		22907AC22F2864450015F3D0 /* IGListItemUpdatesCollectorTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 22907AC02F2864450015F3D0 /* IGListItemUpdatesCollectorTests.m */; };
+		22907AC42F2866160015F3D0 /* IGListUpdateCoalescerTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 22907AC32F2866160015F3D0 /* IGListUpdateCoalescerTests.m */; };
+		22907AC52F2866160015F3D0 /* IGListUpdateCoalescerTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 22907AC32F2866160015F3D0 /* IGListUpdateCoalescerTests.m */; };
+		22907AC72F28679B0015F3D0 /* UIViewControllerIGListAdapterTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 22907AC62F28679B0015F3D0 /* UIViewControllerIGListAdapterTests.m */; };
+		22907AC82F28679B0015F3D0 /* UIViewControllerIGListAdapterTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 22907AC62F28679B0015F3D0 /* UIViewControllerIGListAdapterTests.m */; };
+		22907ACA2F2870020015F3D0 /* IGListPerformDiffTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 22907AC92F2870020015F3D0 /* IGListPerformDiffTests.m */; };
+		22907ACB2F2870020015F3D0 /* IGListPerformDiffTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 22907AC92F2870020015F3D0 /* IGListPerformDiffTests.m */; };
 		26271C8A1DAE94E40073E116 /* IGTestSingleNibItemDataSource.m in Sources */ = {isa = PBXBuildFile; fileRef = 26271C891DAE94E40073E116 /* IGTestSingleNibItemDataSource.m */; };
 		26271C8C1DAE96740073E116 /* IGListSingleNibItemControllerTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 26271C8B1DAE96740073E116 /* IGListSingleNibItemControllerTests.m */; };
 		290DF3771E9323E6009FE456 /* IGListDebuggerTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 290DF3761E9323E6009FE456 /* IGListDebuggerTests.m */; };
@@ -639,6 +649,11 @@
 		16B71CE822B0A08300FE96ED /* IGTestInvalidateLayoutDataSource.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = IGTestInvalidateLayoutDataSource.m; sourceTree = "<group>"; };
 		16B71CE922B0A08300FE96ED /* IGTestInvalidateLayoutObject.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = IGTestInvalidateLayoutObject.h; sourceTree = "<group>"; };
 		16B71CEA22B0A08300FE96ED /* IGTestInvalidateLayoutObject.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = IGTestInvalidateLayoutObject.m; sourceTree = "<group>"; };
+		22907ABC2F2862830015F3D0 /* IGListViewVisibilityTrackerTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = IGListViewVisibilityTrackerTests.m; sourceTree = "<group>"; };
+		22907AC02F2864450015F3D0 /* IGListItemUpdatesCollectorTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = IGListItemUpdatesCollectorTests.m; sourceTree = "<group>"; };
+		22907AC32F2866160015F3D0 /* IGListUpdateCoalescerTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = IGListUpdateCoalescerTests.m; sourceTree = "<group>"; };
+		22907AC62F28679B0015F3D0 /* UIViewControllerIGListAdapterTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = UIViewControllerIGListAdapterTests.m; sourceTree = "<group>"; };
+		22907AC92F2870020015F3D0 /* IGListPerformDiffTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = IGListPerformDiffTests.m; sourceTree = "<group>"; };
 		26271C881DAE94E40073E116 /* IGTestSingleNibItemDataSource.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = IGTestSingleNibItemDataSource.h; sourceTree = "<group>"; };
 		26271C891DAE94E40073E116 /* IGTestSingleNibItemDataSource.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = IGTestSingleNibItemDataSource.m; sourceTree = "<group>"; };
 		26271C8B1DAE96740073E116 /* IGListSingleNibItemControllerTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = IGListSingleNibItemControllerTests.m; sourceTree = "<group>"; };
@@ -1357,7 +1372,9 @@
 				88144EE91D870EDC007C7F66 /* IGListDisplayHandlerTests.m */,
 				29DA5CA21EA7C72400113926 /* IGListGenericSectionControllerTests.m */,
 				F1ED68AE29E9B3B9003744F8 /* IGListInteractiveMovingTests.m */,
+				22907AC02F2864450015F3D0 /* IGListItemUpdatesCollectorTests.m */,
 				88144EEB1D870EDC007C7F66 /* IGListKitTests-Bridging-Header.h */,
+				22907AC92F2870020015F3D0 /* IGListPerformDiffTests.m */,
 				F18CC76529EFBC3800DC3B9A /* IGListReloadDataUpdaterTests.m */,
 				F1E6302229EA43080060B4D6 /* IGListSectionControllerTests.m */,
 				829D7BA81DD1816400549816 /* IGListSectionMapTests.m */,
@@ -1368,7 +1385,10 @@
 				29DA5CA61EA7D37000113926 /* IGListTestCase.m */,
 				29DA5CAA1EA7D3FF00113926 /* IGListTestHelpers.h */,
 				F1ED68B029E9B3B9003744F8 /* IGListTransactionTests.m */,
+				22907AC32F2866160015F3D0 /* IGListUpdateCoalescerTests.m */,
 				88144EEF1D870EDC007C7F66 /* IGListWorkingRangeHandlerTests.m */,
+				22907ABC2F2862830015F3D0 /* IGListViewVisibilityTrackerTests.m */,
+				22907AC62F28679B0015F3D0 /* UIViewControllerIGListAdapterTests.m */,
 				887D0B571D870E1E009E01F7 /* Info.plist */,
 				88144EF01D870EDC007C7F66 /* Objects */,
 			);
@@ -1861,7 +1881,7 @@
 				BuildIndependentTargetsInParallel = YES;
 				CLASSPREFIX = IG;
 				LastSwiftUpdateCheck = 1120;
-				LastUpgradeCheck = 2600;
+				LastUpgradeCheck = 2620;
 				ORGANIZATIONNAME = Instagram;
 				TargetAttributes = {
 					7A02D01C2361520200B49FAE = {
@@ -2188,6 +2208,7 @@
 				828540511DE40D2D00118B94 /* IGListTestAdapterHorizontalDataSource.m in Sources */,
 				885FE2371DC51B76009CE2B4 /* IGListWorkingRangeHandlerTests.m in Sources */,
 				8285404D1DE40C6E00118B94 /* IGListTestHorizontalSection.m in Sources */,
+				22907ACA2F2870020015F3D0 /* IGListPerformDiffTests.m in Sources */,
 				298DDA061E3AE2B000F76F50 /* IGTestNumberBindableCell.m in Sources */,
 				885FE2381DC51B86009CE2B4 /* IGListTestAdapterDataSource.m in Sources */,
 				F1ED68B529E9B3B9003744F8 /* IGListDebugDescriptionTests.m in Sources */,
@@ -2197,9 +2218,11 @@
 				F1ED68B729E9B3B9003744F8 /* IGListTransactionTests.m in Sources */,
 				F1ED68BE29E9B41A003744F8 /* IGListContentInsetTests.m in Sources */,
 				5766613F2CB5A72500E20F73 /* IGListAdapterDelegateAnnouncerTests.m in Sources */,
+				22907ABD2F2862830015F3D0 /* IGListViewVisibilityTrackerTests.m in Sources */,
 				885FE2421DC51B86009CE2B4 /* IGTestSingleStoryboardItemDataSource.m in Sources */,
 				885FE2301DC51B76009CE2B4 /* IGListDiffTests.m in Sources */,
 				885FE22E1DC51B76009CE2B4 /* IGListBatchUpdateDataTests.m in Sources */,
+				22907AC72F28679B0015F3D0 /* UIViewControllerIGListAdapterTests.m in Sources */,
 				298DDA3C1E3B170300F76F50 /* IGLayoutTestSection.m in Sources */,
 				298DDA0A1E3AE31E00F76F50 /* IGTestDiffingSectionController.m in Sources */,
 				29C4748D1DDF45F900AE68CE /* IGListAdapterProxyTests.m in Sources */,
@@ -2219,7 +2242,9 @@
 				885FE2431DC51B86009CE2B4 /* IGTestStoryboardViewController.m in Sources */,
 				F1ED68BC29E9B411003744F8 /* IGListDebuggerTests.m in Sources */,
 				885FE23A1DC51B86009CE2B4 /* IGListTestSection.m in Sources */,
+				22907AC52F2866160015F3D0 /* IGListUpdateCoalescerTests.m in Sources */,
 				29C579301DE0DA8A003A149B /* IGListTestStoryboardSection.m in Sources */,
+				22907AC22F2864450015F3D0 /* IGListItemUpdatesCollectorTests.m in Sources */,
 				885FE23E1DC51B86009CE2B4 /* IGTestDelegateDataSource.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -2314,6 +2339,7 @@
 				13DF01771FA1000E0092A320 /* IGTestReorderableSection.m in Sources */,
 				829D7BAA1DD1819000549816 /* IGListSectionMapTests.m in Sources */,
 				F1ED68BD29E9B415003744F8 /* IGListDebugDescriptionTests.m in Sources */,
+				22907ACB2F2870020015F3D0 /* IGListPerformDiffTests.m in Sources */,
 				E56B7B3420A9D7100071010C /* IGListCollectionScrollingTraitsTests.m in Sources */,
 				16B71CEB22B0A08400FE96ED /* IGTestInvalidateLayoutSectionController.m in Sources */,
 				29C5792E1DE0DA89003A149B /* IGTestNibSupplementaryView.m in Sources */,
@@ -2323,9 +2349,11 @@
 				821BC4D31DB981AB00172ED0 /* IGTestSingleStoryboardItemDataSource.m in Sources */,
 				298DDA3D1E3B170400F76F50 /* IGLayoutTestSection.m in Sources */,
 				5766613E2CB5A72500E20F73 /* IGListAdapterDelegateAnnouncerTests.m in Sources */,
+				22907ABE2F2862830015F3D0 /* IGListViewVisibilityTrackerTests.m in Sources */,
 				298DDA091E3AE31D00F76F50 /* IGTestDiffingSectionController.m in Sources */,
 				88144F151D870EDC007C7F66 /* IGListTestSection.m in Sources */,
 				82914C5B1E6E2DEC0066C2F8 /* IGListTestContainerSizeSection.m in Sources */,
+				22907AC82F28679B0015F3D0 /* UIViewControllerIGListAdapterTests.m in Sources */,
 				29DA5CA71EA7D37000113926 /* IGListTestCase.m in Sources */,
 				88144F1D1D870EDC007C7F66 /* IGTestSupplementarySource.m in Sources */,
 				F18CC76629EFBC3800DC3B9A /* IGListReloadDataUpdaterTests.m in Sources */,
@@ -2345,7 +2373,9 @@
 				F18CC75C29EFBB9400DC3B9A /* IGListCollectionViewTests.m in Sources */,
 				8240C7F81DC2F3FB00B3AAE7 /* IGListTestStoryboardSection.m in Sources */,
 				F18CC76329EFBBE200DC3B9A /* IGTestBindingSingleItemDataSource.m in Sources */,
+				22907AC42F2866160015F3D0 /* IGListUpdateCoalescerTests.m in Sources */,
 				26271C8A1DAE94E40073E116 /* IGTestSingleNibItemDataSource.m in Sources */,
+				22907AC12F2864450015F3D0 /* IGListItemUpdatesCollectorTests.m in Sources */,
 				6A9EB3611F841E5D0070C572 /* IGTestSingleWithoutDeselectionDelegate.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

IGListKit.xcodeproj/xcshareddata/xcschemes/IGListKit-macOS.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "2600"
+   LastUpgradeVersion = "2620"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"

IGListKit.xcodeproj/xcshareddata/xcschemes/IGListKit-tvOS.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "2600"
+   LastUpgradeVersion = "2620"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"

IGListKit.xcodeproj/xcshareddata/xcschemes/IGListKit.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "2600"
+   LastUpgradeVersion = "2620"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"

Source/IGListKit/IGListAdapterUpdaterDelegate.h

@@ -181,8 +181,16 @@ willPerformBatchUpdatesWithCollectionView:(UICollectionView *)collectionView
                 diffResult:(IGListIndexSetResult *)diffResult
                    updates:(IGListBatchUpdateData *)updates;
 
+/**
+ Notifies the delegate that the updater detected an imminent crash, such as when a section controller returns a nil cell.
+ This provides an opportunity to log diagnostic information before the crash occurs.
+
+ @param listAdapterUpdater The adapter updater that detected the issue.
+ @param collectionView The collection view involved in the crash.
+ @param sectionControllerClass The class of the section controller that caused the issue, if available.
+ */
 - (void)     listAdapterUpdater:(IGListAdapterUpdater *)listAdapterUpdater
-    willCrashWithCollectionView:collectionView
+    willCrashWithCollectionView:(UICollectionView *)collectionView
     sectionControllerClass:(nullable Class)sectionControllerClass;
 
 /**

Source/IGListKit/IGListUpdatingDelegate.h

@@ -202,6 +202,13 @@ NS_SWIFT_NAME(ListUpdatingDelegate)
  */
 - (BOOL)isInDataUpdateBlock;
 
+/**
+ Called when the updater detects an imminent crash, such as when a section controller returns a nil cell.
+ This provides an opportunity to log diagnostic information before the crash occurs.
+
+ @param collectionView The collection view involved in the crash.
+ @param sectionControllerClass The class of the section controller that caused the issue, if available.
+ */
 - (void)willCrashWithCollectionView:(UICollectionView *)collectionView
              sectionControllerClass:(nullable Class)sectionControllerClass;
 

Tests/IGListAdapterDelegateAnnouncerTests.m

@@ -137,6 +137,31 @@ - (void)test_whenRemovignOneItem_withTwoListeners_withOneAdapter_thatBothListene
     [self waitForExpectationsWithTimeout:30 handler:nil];
 }
 
+#pragma mark - Remove listener
+
+- (void)test_whenRemovingListener_thatListenerDoesNotReceiveCallbacks {
+    [self setupAdapter1WithObjects:@[]];
+
+    IGTestObject *const object = genTestObject(@1, @1);
+    self.dataSource1.objects = @[object];
+
+    id mockDisplayHandler = [OCMockObject mockForProtocol:@protocol(IGListAdapterDelegate)];
+    [self.announcer addListener:mockDisplayHandler];
+    [self.announcer removeListener:mockDisplayHandler];
+
+    // Listener was removed, so it should NOT receive any callbacks
+    [[mockDisplayHandler reject] listAdapter:[OCMArg any] willDisplayObject:[OCMArg any] atIndex:0];
+    [[mockDisplayHandler reject] listAdapter:[OCMArg any] willDisplayObject:[OCMArg any] cell:[OCMArg any] atIndexPath:[OCMArg any]];
+
+    XCTestExpectation *expectation = genExpectation;
+    [self.adapter1 performUpdatesAnimated:NO completion:^(BOOL finished) {
+        [mockDisplayHandler verify];
+        XCTAssertTrue(finished);
+        [expectation fulfill];
+    }];
+    [self waitForExpectationsWithTimeout:30 handler:nil];
+}
+
 #pragma mark - Two adapters, single listener
 
 - (void)test_whenShowingTwoItems_withOneListeners_withTwoAdapters_thatBothItemsSendWillDisplay {

Tests/IGListAdapterE2ETests.m

@@ -2727,4 +2727,116 @@ - (void)test_whenPerformingUpdates_withAdaptiveCoalescing_thatCollectionViewCoun
     [self waitForExpectationsWithTimeout:30 handler:nil];
 }
 
+- (void)test_whenPerformingUpdates_withAdaptiveDiffingHigherQOS_thatCollectionViewUpdates {
+    IGListAdapterUpdater *updater = (IGListAdapterUpdater *)self.updater;
+    updater.allowsBackgroundDiffing = YES;
+    updater.adaptiveDiffingExperimentConfig = (IGListAdaptiveDiffingExperimentConfig) {
+        .enabled = YES,
+        .higherQOSEnabled = YES,
+        .maxItemCountToRunOnMain = 0,
+        .lowerPriorityWhenViewNotVisible = NO
+    };
+
+    [self setupWithObjects:@[
+        genTestObject(@1, @1),
+        genTestObject(@2, @2),
+    ]];
+
+    self.dataSource.objects = @[
+        genTestObject(@2, @2),
+        genTestObject(@3, @3),
+    ];
+
+    XCTestExpectation *expectation = genExpectation;
+    [self.adapter performUpdatesAnimated:YES completion:^(BOOL finished) {
+        XCTAssertEqual([self.collectionView numberOfSections], 2);
+        [expectation fulfill];
+    }];
+    [self waitForExpectationsWithTimeout:30 handler:nil];
+}
+
+- (void)test_whenPerformingUpdates_withAdaptiveDiffingLowerPriorityWhenNotVisible_thatCollectionViewUpdates {
+    IGListAdapterUpdater *updater = (IGListAdapterUpdater *)self.updater;
+    updater.allowsBackgroundDiffing = YES;
+    updater.adaptiveDiffingExperimentConfig = (IGListAdaptiveDiffingExperimentConfig) {
+        .enabled = YES,
+        .higherQOSEnabled = NO,
+        .maxItemCountToRunOnMain = 0,
+        .lowerPriorityWhenViewNotVisible = YES
+    };
+
+    // Remove from window to make it "not visible"
+    [self.collectionView removeFromSuperview];
+
+    [self setupWithObjects:@[
+        genTestObject(@1, @1),
+        genTestObject(@2, @2),
+    ]];
+
+    self.dataSource.objects = @[
+        genTestObject(@2, @2),
+        genTestObject(@3, @3),
+    ];
+
+    XCTestExpectation *expectation = genExpectation;
+    [self.adapter performUpdatesAnimated:NO completion:^(BOOL finished) {
+        XCTAssertEqual([self.collectionView numberOfSections], 2);
+        [expectation fulfill];
+    }];
+    [self waitForExpectationsWithTimeout:30 handler:nil];
+}
+
+- (void)test_whenPerformingUpdates_withAdaptiveDiffingSmallItemCount_thatDiffRunsOnMain {
+    IGListAdapterUpdater *updater = (IGListAdapterUpdater *)self.updater;
+    updater.allowsBackgroundDiffing = YES;
+    updater.adaptiveDiffingExperimentConfig = (IGListAdaptiveDiffingExperimentConfig) {
+        .enabled = YES,
+        .higherQOSEnabled = NO,
+        .maxItemCountToRunOnMain = 100, // Item count is under this threshold
+        .lowerPriorityWhenViewNotVisible = NO
+    };
+
+    [self setupWithObjects:@[
+        genTestObject(@1, @1),
+    ]];
+
+    self.dataSource.objects = @[
+        genTestObject(@1, @1),
+        genTestObject(@2, @2),
+    ];
+
+    XCTestExpectation *expectation = genExpectation;
+    [self.adapter performUpdatesAnimated:YES completion:^(BOOL finished) {
+        XCTAssertEqual([self.collectionView numberOfSections], 2);
+        [expectation fulfill];
+    }];
+    [self waitForExpectationsWithTimeout:30 handler:nil];
+}
+
+- (void)test_whenPerformingUpdates_withAdaptiveDiffingBackgroundDisabled_thatDiffRunsOnMain {
+    IGListAdapterUpdater *updater = (IGListAdapterUpdater *)self.updater;
+    updater.allowsBackgroundDiffing = NO;
+    updater.adaptiveDiffingExperimentConfig = (IGListAdaptiveDiffingExperimentConfig) {
+        .enabled = YES,
+        .higherQOSEnabled = YES,
+        .maxItemCountToRunOnMain = 0,
+        .lowerPriorityWhenViewNotVisible = YES
+    };
+
+    [self setupWithObjects:@[
+        genTestObject(@1, @1),
+    ]];
+
+    self.dataSource.objects = @[
+        genTestObject(@2, @2),
+    ];
+
+    XCTestExpectation *expectation = genExpectation;
+    [self.adapter performUpdatesAnimated:YES completion:^(BOOL finished) {
+        XCTAssertEqual([self.collectionView numberOfSections], 1);
+        [expectation fulfill];
+    }];
+    [self waitForExpectationsWithTimeout:30 handler:nil];
+}
+
 @end