feat(ui): update scrollable_positioned_list with the latest changes.

Signed-off-by: xsahil03x <[email protected]>

packages/stream_chat_flutter/test/scrollable_positioned_list/horizontal_scrollable_positioned_list_test.dart

@@ -2,13 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
-
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:pedantic/pedantic.dart';
 import 'package:stream_chat_flutter/scrollable_positioned_list/scrollable_positioned_list.dart';
 
-const screenHeight = 400.0;
+const screenHeight = 100.0;
 const screenWidth = 400.0;
 const itemWidth = screenWidth / 10.0;
 const itemCount = 500;
@@ -46,6 +45,11 @@ void main() {
     );
   }
 
+  final fadeTransitionFinder = find.descendant(
+    of: find.byType(ScrollablePositionedList),
+    matching: find.byType(FadeTransition),
+  );
+
   testWidgets('List positioned with 0 at left', (WidgetTester tester) async {
     final itemPositionsListener = ItemPositionsListener.create();
     await setUpWidgetTest(tester, itemPositionsListener: itemPositionsListener);
@@ -172,7 +176,7 @@ void main() {
     await tester.pumpAndSettle();
 
     expect(tester.getTopLeft(find.text('Item 100')).dx, 0);
-    expect(tester.getBottomRight(find.text('Item 109')).dy, screenWidth);
+    expect(tester.getBottomRight(find.text('Item 109')).dy, screenHeight);
 
     expect(
         itemPositionsListener.itemPositions.value
@@ -196,6 +200,31 @@ void main() {
         1);
   });
 
+  testWidgets('Scroll to 20 without fading', (WidgetTester tester) async {
+    final itemScrollController = ItemScrollController();
+    final itemPositionsListener = ItemPositionsListener.create();
+    await setUpWidgetTest(tester,
+        itemScrollController: itemScrollController,
+        itemPositionsListener: itemPositionsListener);
+
+    var fadeTransition = tester.widget<FadeTransition>(fadeTransitionFinder);
+    final initialOpacity = fadeTransition.opacity;
+
+    unawaited(
+        itemScrollController.scrollTo(index: 20, duration: scrollDuration));
+    await tester.pump();
+    await tester.pump();
+    await tester.pump(scrollDuration ~/ 2);
+
+    fadeTransition = tester.widget<FadeTransition>(fadeTransitionFinder);
+    expect(fadeTransition.opacity, initialOpacity);
+
+    await tester.pumpAndSettle();
+
+    expect(find.text('Item 14'), findsNothing);
+    expect(find.text('Item 20'), findsOneWidget);
+  });
+
   testWidgets('padding test - centered sliver at left',
       (WidgetTester tester) async {
     final itemScrollController = ItemScrollController();

packages/stream_chat_flutter/test/scrollable_positioned_list/positioned_list_test.dart

@@ -360,4 +360,55 @@ void main() {
             .itemTrailingEdge,
         1);
   });
+
+  testWidgets('Does not crash when updated offscreen',
+      (WidgetTester tester) async {
+    late StateSetter setState;
+    var updated = false;
+
+    // There's 0 relayout boundaries in this subtree.
+    final widget = StatefulBuilder(builder: (context, stateSetter) {
+      setState = stateSetter;
+      return Positioned(
+          left: 0,
+          right: 0,
+          child: PositionedList(
+            shrinkWrap: true,
+            itemCount: 1,
+            // When `updated` becomes true this line inserts a
+            // RenderIndexedSemantics to the render tree.
+            addSemanticIndexes: updated,
+            itemBuilder: (context, index) => const SizedBox(height: itemHeight),
+          ));
+    });
+
+    await tester.pumpWidget(Directionality(
+      textDirection: TextDirection.ltr,
+      child: Overlay(
+        initialEntries: [
+          OverlayEntry(builder: (context) => widget, maintainState: true),
+        ],
+      ),
+    ));
+
+    // Insert a new opaque OverlayEntry that would prevent the first OverlayEntry
+    // from doing re-layout. Since there's no relayout boundaries in the first
+    // OverlayEntry, no dirty RenderObjects in its render subtree can update
+    // layout.
+    final newOverlay =
+        OverlayEntry(builder: (context) => const SizedBox.expand(), opaque: true);
+    tester.state<OverlayState>(find.byType(Overlay)).insert(newOverlay);
+    await tester.pump();
+
+    // Update the list item's render tree. A new RenderObjectElement is
+    // inflated, registeredElement.renderObject will point to this new
+    // RenderObjectElement's RenderObject (RenderIndexedSemantics), which has
+    // never been laid out.
+    setState(() {
+      updated = true;
+    });
+
+    await tester.pump();
+    expect(tester.takeException(), isNull);
+  });
 }

packages/stream_chat_flutter/test/scrollable_positioned_list/reversed_scrollable_positioned_list_test.dart

@@ -2,10 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
-
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:pedantic/pedantic.dart';
 import 'package:stream_chat_flutter/scrollable_positioned_list/scrollable_positioned_list.dart';
 
 const screenHeight = 400.0;

packages/stream_chat_flutter/test/scrollable_positioned_list/scrollable_positioned_list_test.dart

@@ -2,12 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
 import 'dart:math';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:pedantic/pedantic.dart';
 import 'package:stream_chat_flutter/scrollable_positioned_list/scrollable_positioned_list.dart';
 import 'package:stream_chat_flutter/scrollable_positioned_list/src/scroll_view.dart';
 
@@ -48,8 +48,7 @@ void main() {
           itemCount: itemCount,
           itemScrollController: itemScrollController,
           itemBuilder: (context, index) {
-            assert(index >= 0 && index <= itemCount - 1,
-                '''index needs to be bigger or equal to 0 and smallert than itemCount -1''');
+            assert(index >= 0 && index <= itemCount - 1);
             return SizedBox(
               height:
                   variableHeight ? (itemHeight + (index % 13) * 5) : itemHeight,
@@ -71,6 +70,11 @@ void main() {
     );
   }
 
+  final fadeTransitionFinder = find.descendant(
+    of: find.byType(ScrollablePositionedList),
+    matching: find.byType(FadeTransition),
+  );
+
   testWidgets('List positioned with 0 at top', (WidgetTester tester) async {
     final itemPositionsListener = ItemPositionsListener.create();
     await setUpWidgetTest(tester, itemPositionsListener: itemPositionsListener);
@@ -394,11 +398,7 @@ void main() {
         itemScrollController: itemScrollController,
         itemPositionsListener: itemPositionsListener);
 
-    var fadeTransition = tester.widget<FadeTransition>(find
-        .descendant(
-            of: find.byType(ScrollablePositionedList),
-            matching: find.byType(FadeTransition))
-        .last);
+    var fadeTransition = tester.widget<FadeTransition>(fadeTransitionFinder);
     final initialOpacity = fadeTransition.opacity;
 
     unawaited(
@@ -407,11 +407,7 @@ void main() {
     await tester.pump();
     await tester.pump(scrollDuration ~/ 2);
 
-    fadeTransition = tester.widget<FadeTransition>(find
-        .descendant(
-            of: find.byType(ScrollablePositionedList),
-            matching: find.byType(FadeTransition))
-        .last);
+    fadeTransition = tester.widget<FadeTransition>(fadeTransitionFinder);
     expect(fadeTransition.opacity, initialOpacity);
 
     await tester.pumpAndSettle();
@@ -456,10 +452,6 @@ void main() {
     final itemScrollController = ItemScrollController();
     await setUpWidgetTest(tester, itemScrollController: itemScrollController);
 
-    final fadeTransitionFinder = find.descendant(
-        of: find.byType(ScrollablePositionedList),
-        matching: find.byType(FadeTransition));
-
     unawaited(
         itemScrollController.scrollTo(index: 100, duration: scrollDuration));
     await tester.pump();
@@ -533,26 +525,14 @@ void main() {
     await tester.pump();
     await tester.pump();
     expect(
-        tester
-            .widget<FadeTransition>(find
-                .descendant(
-                    of: find.byType(ScrollablePositionedList),
-                    matching: find.byType(FadeTransition))
-                .last)
-            .opacity
-            .value,
-        closeTo(0, 0.01));
+      tester.widget<FadeTransition>(fadeTransitionFinder.last).opacity.value,
+      closeTo(0, 0.01),
+    );
     await tester.pump(scrollDuration + scrollDurationTolerance);
     expect(
-        tester
-            .widget<FadeTransition>(find
-                .descendant(
-                    of: find.byType(ScrollablePositionedList),
-                    matching: find.byType(FadeTransition))
-                .last)
-            .opacity
-            .value,
-        closeTo(1, 0.01));
+      tester.widget<FadeTransition>(fadeTransitionFinder.last).opacity.value,
+      closeTo(1, 0.01),
+    );
 
     expect(find.text('Item 0'), findsOneWidget);
     expect(tester.getTopLeft(find.text('Item 0')).dy, 0);
@@ -610,15 +590,9 @@ void main() {
     expect(tester.getTopLeft(find.text('Item 10')).dy, 0);
     expect(tester.getBottomLeft(find.text('Item 19')).dy, screenHeight);
     expect(
-        tester
-            .widget<FadeTransition>(find
-                .descendant(
-                    of: find.byType(ScrollablePositionedList),
-                    matching: find.byType(FadeTransition))
-                .last)
-            .opacity
-            .value,
-        closeTo(0.5, 0.01));
+      tester.widget<FadeTransition>(fadeTransitionFinder.last).opacity.value,
+      closeTo(0.5, 0.01),
+    );
 
     await tester.pumpAndSettle();
   });
@@ -899,11 +873,7 @@ void main() {
     await tester.pump();
 
     expect(tester.getTopLeft(find.text('Item 9')).dy, 0);
-    final fadeTransition = tester.widget<FadeTransition>(find
-        .descendant(
-            of: find.byType(ScrollablePositionedList),
-            matching: find.byType(FadeTransition))
-        .last);
+    final fadeTransition = tester.widget<FadeTransition>(fadeTransitionFinder);
     expect(fadeTransition.opacity.value, 1.0);
 
     await tester.pumpAndSettle();
@@ -923,21 +893,12 @@ void main() {
     await tester.pump();
 
     expect(tester.getTopLeft(find.text('Item 10')).dy, 0);
-    final fadeTransition = tester.widget<FadeTransition>(find
-        .descendant(
-            of: find.byType(ScrollablePositionedList),
-            matching: find.byType(FadeTransition))
-        .last);
+    final fadeTransition = tester.widget<FadeTransition>(fadeTransitionFinder);
     expect(fadeTransition.opacity.value, 1.0);
 
     await tester.pumpAndSettle();
   });
 
-  final fadeTransitionFinder = find.descendant(
-    of: find.byType(ScrollablePositionedList),
-    matching: find.byType(FadeTransition),
-  );
-
   testWidgets('Scroll to 0 stop before half way', (WidgetTester tester) async {
     final itemScrollController = ItemScrollController();
     await setUpWidgetTest(tester, itemScrollController: itemScrollController);
@@ -1022,14 +983,13 @@ void main() {
         itemScrollController.scrollTo(index: 0, duration: scrollDuration));
     await tester.pump();
     await tester.pump();
-    await tester.pump(scrollDuration ~/ 2 + scrollDuration ~/ 20);
+    await tester.pump(scrollDuration ~/ 2);
 
     await tester.tap(find.byType(ScrollablePositionedList));
     await tester.pump();
 
-    expect(tester.getTopLeft(find.text('Item 9')).dy, closeTo(0, tolerance));
-    final fadeTransition = tester.widget<FadeTransition>(fadeTransitionFinder);
-    expect(fadeTransition.opacity.value, 1.0);
+    expect(tester.getTopLeft(find.text('Item 90')).dy, 0);
+    expect(fadeTransitionFinder, findsNWidgets(1));
 
     await tester.pumpAndSettle();
   });
@@ -1098,6 +1058,34 @@ void main() {
     expect(find.text('Item 100'), findsNothing);
   });
 
+  testWidgets("Second scroll future doesn't complete until scroll is done",
+      (WidgetTester tester) async {
+    final itemScrollController = ItemScrollController();
+    await setUpWidgetTest(tester, itemScrollController: itemScrollController);
+
+    unawaited(
+        itemScrollController.scrollTo(index: 100, duration: scrollDuration));
+    await tester.pump();
+    await tester.pump();
+    await tester.pump(scrollDuration ~/ 2);
+
+    final scrollFuture2 =
+        itemScrollController.scrollTo(index: 250, duration: scrollDuration);
+
+    var futureComplete = false;
+    unawaited(scrollFuture2.then((_) => futureComplete = true));
+
+    await tester.pump();
+    await tester.pump();
+    await tester.pump(scrollDuration ~/ 2);
+
+    expect(futureComplete, isFalse);
+
+    await tester.pumpAndSettle();
+
+    expect(futureComplete, isTrue);
+  });
+
   testWidgets('Scroll to 250, scroll to 100, scroll to 0 half way',
       (WidgetTester tester) async {
     final itemScrollController = ItemScrollController();
@@ -1145,7 +1133,7 @@ void main() {
   }, skip: true);
 
   testWidgets(
-      '''Jump to 400 at bottom, manually scroll, scroll to 100 at bottom and back''',
+      'Jump to 400 at bottom, manually scroll, scroll to 100 at bottom and back',
       (WidgetTester tester) async {
     final itemScrollController = ItemScrollController();
     final itemPositionsListener = ItemPositionsListener.create();
@@ -1664,7 +1652,7 @@ void main() {
   });
 
   testWidgets(
-      '''Maintain programmatic and user position (9 half way off top) in page view''',
+      'Maintain programmatic and user position (9 half way off top) in page view',
       (WidgetTester tester) async {
     final itemPositionsListener = ItemPositionsListener.create();
     final itemScrollController = ItemScrollController();
@@ -1751,21 +1739,21 @@ void main() {
       MaterialApp(
         home: ValueListenableBuilder<int>(
           valueListenable: itemCount,
-          builder: (context, itemCount, child) =>
-              ScrollablePositionedList.builder(
-            initialScrollIndex: min(100, itemCount),
-            itemCount: itemCount,
-            itemScrollController: itemScrollController,
-            itemPositionsListener: itemPositionsListener,
-            itemBuilder: (context, index) {
-              assert(index >= 0 && index <= itemCount - 1,
-                  'index not bigger than 0 and smaller than itemCount - 1');
-              return SizedBox(
-                height: itemHeight,
-                child: Text('Item $index'),
-              );
-            },
-          ),
+          builder: (context, itemCount, child) {
+            return ScrollablePositionedList.builder(
+              initialScrollIndex: min(100, itemCount),
+              itemCount: itemCount,
+              itemScrollController: itemScrollController,
+              itemPositionsListener: itemPositionsListener,
+              itemBuilder: (context, index) {
+                assert(index >= 0 && index <= itemCount - 1);
+                return SizedBox(
+                  height: itemHeight,
+                  child: Text('Item $index'),
+                );
+              },
+            );
+          },
         ),
       ),
     );
@@ -1795,19 +1783,19 @@ void main() {
       MaterialApp(
         home: ValueListenableBuilder<int>(
           valueListenable: itemCount,
-          builder: (context, itemCount, child) =>
-              ScrollablePositionedList.builder(
-            initialScrollIndex: min(100, itemCount - 1),
-            itemCount: itemCount,
-            itemBuilder: (context, index) {
-              assert(index >= 0 && index <= itemCount - 1,
-                  'index not bigger than 0 and smaller than itemCount -1');
-              return SizedBox(
-                height: itemHeight,
-                child: Text('Item $index'),
-              );
-            },
-          ),
+          builder: (context, itemCount, child) {
+            return ScrollablePositionedList.builder(
+              initialScrollIndex: min(100, itemCount - 1),
+              itemCount: itemCount,
+              itemBuilder: (context, index) {
+                assert(index >= 0 && index <= itemCount - 1);
+                return SizedBox(
+                  height: itemHeight,
+                  child: Text('Item $index'),
+                );
+              },
+            );
+          },
         ),
       ),
     );
@@ -1834,19 +1822,19 @@ void main() {
       MaterialApp(
         home: ValueListenableBuilder<int>(
           valueListenable: itemCount,
-          builder: (context, itemCount, child) =>
-              ScrollablePositionedList.builder(
-            initialScrollIndex: itemCount - 1,
-            itemCount: itemCount,
-            itemBuilder: (context, index) {
-              assert(index >= 0 && index <= itemCount - 1,
-                  'index not bigger than 0 and smaller than itemCount -1');
-              return SizedBox(
-                height: itemHeight,
-                child: Text('Item $index'),
-              );
-            },
-          ),
+          builder: (context, itemCount, child) {
+            return ScrollablePositionedList.builder(
+              initialScrollIndex: itemCount - 1,
+              itemCount: itemCount,
+              itemBuilder: (context, index) {
+                assert(index >= 0 && index <= itemCount - 1);
+                return SizedBox(
+                  height: itemHeight,
+                  child: Text('Item $index'),
+                );
+              },
+            );
+          },
         ),
       ),
     );
@@ -1878,11 +1866,7 @@ void main() {
       minCacheExtent: 10,
     );
 
-    var fadeTransition = tester.widget<FadeTransition>(find
-        .descendant(
-            of: find.byType(ScrollablePositionedList),
-            matching: find.byType(FadeTransition))
-        .last);
+    var fadeTransition = tester.widget<FadeTransition>(fadeTransitionFinder);
     final initialOpacity = fadeTransition.opacity;
 
     unawaited(
@@ -1891,11 +1875,7 @@ void main() {
     await tester.pump();
     await tester.pump(scrollDuration ~/ 2);
 
-    fadeTransition = tester.widget<FadeTransition>(find
-        .descendant(
-            of: find.byType(ScrollablePositionedList),
-            matching: find.byType(FadeTransition))
-        .last);
+    fadeTransition = tester.widget<FadeTransition>(fadeTransitionFinder);
     expect(fadeTransition.opacity, initialOpacity);
 
     await tester.pumpAndSettle();
@@ -1914,11 +1894,9 @@ void main() {
       minCacheExtent: itemHeight * 200,
     );
 
-    var fadeTransition = tester.widget<FadeTransition>(find
-        .descendant(
-            of: find.byType(ScrollablePositionedList),
-            matching: find.byType(FadeTransition))
-        .last);
+    var fadeTransition = tester.widget<FadeTransition>(
+      fadeTransitionFinder,
+    );
     final initialOpacity = fadeTransition.opacity;
 
     unawaited(
@@ -1927,11 +1905,7 @@ void main() {
     await tester.pump();
     await tester.pump(scrollDuration ~/ 2);
 
-    fadeTransition = tester.widget<FadeTransition>(find
-        .descendant(
-            of: find.byType(ScrollablePositionedList),
-            matching: find.byType(FadeTransition))
-        .last);
+    fadeTransition = tester.widget<FadeTransition>(fadeTransitionFinder);
     expect(fadeTransition.opacity, initialOpacity);
 
     await tester.pumpAndSettle();
@@ -1965,17 +1939,21 @@ void main() {
       MaterialApp(
         home: ValueListenableBuilder<Key>(
           valueListenable: key,
-          builder: (context, key, child) => Container(
-            key: key,
-            child: ScrollablePositionedList.builder(
-              itemCount: 200,
-              itemScrollController: itemScrollController,
-              itemBuilder: (context, index) => SizedBox(
-                height: itemHeight,
-                child: Text('Item $index'),
+          builder: (context, key, child) {
+            return Container(
+              key: key,
+              child: ScrollablePositionedList.builder(
+                itemCount: 200,
+                itemScrollController: itemScrollController,
+                itemBuilder: (context, index) {
+                  return SizedBox(
+                    height: itemHeight,
+                    child: Text('Item $index'),
+                  );
+                },
               ),
-            ),
-          ),
+            );
+          },
         ),
       ),
     );
@@ -2054,15 +2032,19 @@ void main() {
       MaterialApp(
         home: ValueListenableBuilder<Key>(
           valueListenable: key,
-          builder: (context, key, child) => ScrollablePositionedList.builder(
-            key: key,
-            itemCount: 10,
-            itemScrollController: itemScrollController,
-            itemBuilder: (context, index) => SizedBox(
-              height: itemHeight,
-              child: Text('Item $index'),
-            ),
-          ),
+          builder: (context, key, child) {
+            return ScrollablePositionedList.builder(
+              key: key,
+              itemCount: 10,
+              itemScrollController: itemScrollController,
+              itemBuilder: (context, index) {
+                return SizedBox(
+                  height: itemHeight,
+                  child: Text('Item $index'),
+                );
+              },
+            );
+          },
         ),
       ),
     );
@@ -2084,17 +2066,21 @@ void main() {
       MaterialApp(
         home: ValueListenableBuilder<Key>(
           valueListenable: key,
-          builder: (context, key, child) => Container(
-            key: key,
-            child: ScrollablePositionedList.builder(
-              itemCount: 100,
-              itemScrollController: itemScrollController,
-              itemBuilder: (context, index) => SizedBox(
-                height: itemHeight,
-                child: Text('Item $index'),
+          builder: (context, key, child) {
+            return Container(
+              key: key,
+              child: ScrollablePositionedList.builder(
+                itemCount: 100,
+                itemScrollController: itemScrollController,
+                itemBuilder: (context, index) {
+                  return SizedBox(
+                    height: itemHeight,
+                    child: Text('Item $index'),
+                  );
+                },
               ),
-            ),
-          ),
+            );
+          },
         ),
       ),
     );
@@ -2124,18 +2110,22 @@ void main() {
       MaterialApp(
         home: ValueListenableBuilder<Key>(
           valueListenable: containerKey,
-          builder: (context, key, child) => Container(
-            key: key,
-            child: ScrollablePositionedList.builder(
-              key: scrollKey,
-              itemCount: 100,
-              itemScrollController: itemScrollController,
-              itemBuilder: (context, index) => SizedBox(
-                height: itemHeight,
-                child: Text('Item $index'),
+          builder: (context, key, child) {
+            return Container(
+              key: key,
+              child: ScrollablePositionedList.builder(
+                key: scrollKey,
+                itemCount: 100,
+                itemScrollController: itemScrollController,
+                itemBuilder: (context, index) {
+                  return SizedBox(
+                    height: itemHeight,
+                    child: Text('Item $index'),
+                  );
+                },
               ),
-            ),
-          ),
+            );
+          },
         ),
       ),
     );
@@ -2166,15 +2156,18 @@ void main() {
       MaterialApp(
         home: ValueListenableBuilder<ItemScrollController>(
           valueListenable: itemScrollControllerListenable,
-          builder: (context, itemScrollController, child) =>
-              ScrollablePositionedList.builder(
-            itemCount: 100,
-            itemScrollController: itemScrollController,
-            itemBuilder: (context, index) => SizedBox(
-              height: itemHeight,
-              child: Text('Item $index'),
-            ),
-          ),
+          builder: (context, itemScrollController, child) {
+            return ScrollablePositionedList.builder(
+              itemCount: 100,
+              itemScrollController: itemScrollController,
+              itemBuilder: (context, index) {
+                return SizedBox(
+                  height: itemHeight,
+                  child: Text('Item $index'),
+                );
+              },
+            );
+          },
         ),
       ),
     );
@@ -2215,29 +2208,35 @@ void main() {
           Expanded(
             child: ValueListenableBuilder<ItemScrollController>(
               valueListenable: topItemScrollControllerListenable,
-              builder: (context, itemScrollController, child) =>
-                  ScrollablePositionedList.builder(
-                itemCount: 100,
-                itemScrollController: itemScrollController,
-                itemBuilder: (context, index) => SizedBox(
-                  height: itemHeight,
-                  child: Text('Item $index'),
-                ),
-              ),
+              builder: (context, itemScrollController, child) {
+                return ScrollablePositionedList.builder(
+                  itemCount: 100,
+                  itemScrollController: itemScrollController,
+                  itemBuilder: (context, index) {
+                    return SizedBox(
+                      height: itemHeight,
+                      child: Text('Item $index'),
+                    );
+                  },
+                );
+              },
             ),
           ),
           Expanded(
             child: ValueListenableBuilder<ItemScrollController>(
               valueListenable: bottomItemScrollControllerListenable,
-              builder: (context, itemScrollController, child) =>
-                  ScrollablePositionedList.builder(
-                itemCount: 100,
-                itemScrollController: itemScrollController,
-                itemBuilder: (context, index) => SizedBox(
-                  height: itemHeight,
-                  child: Text('Item $index'),
-                ),
-              ),
+              builder: (context, itemScrollController, child) {
+                return ScrollablePositionedList.builder(
+                  itemCount: 100,
+                  itemScrollController: itemScrollController,
+                  itemBuilder: (context, index) {
+                    return SizedBox(
+                      height: itemHeight,
+                      child: Text('Item $index'),
+                    );
+                  },
+                );
+              },
             ),
           ),
         ],

packages/stream_chat_flutter/test/scrollable_positioned_list/separated_scrollable_positioned_list_test.dart

@@ -2,10 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
-
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:pedantic/pedantic.dart';
 import 'package:stream_chat_flutter/scrollable_positioned_list/scrollable_positioned_list.dart';
 import 'package:stream_chat_flutter/scrollable_positioned_list/src/scroll_view.dart';
 
@@ -497,20 +496,21 @@ void main() {
       MaterialApp(
         home: ValueListenableBuilder<int>(
           valueListenable: itemCount,
-          builder: (context, itemCount, child) =>
-              ScrollablePositionedList.separated(
-            itemCount: itemCount,
-            itemScrollController: itemScrollController,
-            itemPositionsListener: itemPositionsListener,
-            itemBuilder: (context, index) => SizedBox(
-              height: itemHeight,
-              child: Text('Item $index'),
-            ),
-            separatorBuilder: (context, index) => SizedBox(
-              height: separatorHeight,
-              child: Text('Separator $index'),
-            ),
-          ),
+          builder: (context, itemCount, child) {
+            return ScrollablePositionedList.separated(
+              itemCount: itemCount,
+              itemScrollController: itemScrollController,
+              itemPositionsListener: itemPositionsListener,
+              itemBuilder: (context, index) => SizedBox(
+                height: itemHeight,
+                child: Text('Item $index'),
+              ),
+              separatorBuilder: (context, index) => SizedBox(
+                height: separatorHeight,
+                child: Text('Separator $index'),
+              ),
+            );
+          },
         ),
       ),
     );
@@ -538,20 +538,21 @@ void main() {
       MaterialApp(
         home: ValueListenableBuilder<int>(
           valueListenable: itemCount,
-          builder: (context, itemCount, child) =>
-              ScrollablePositionedList.separated(
-            itemCount: itemCount,
-            itemScrollController: itemScrollController,
-            itemPositionsListener: itemPositionsListener,
-            itemBuilder: (context, index) => SizedBox(
-              height: itemHeight,
-              child: Text('Item $index'),
-            ),
-            separatorBuilder: (context, index) => SizedBox(
-              height: separatorHeight,
-              child: Text('Separator $index'),
-            ),
-          ),
+          builder: (context, itemCount, child) {
+            return ScrollablePositionedList.separated(
+              itemCount: itemCount,
+              itemScrollController: itemScrollController,
+              itemPositionsListener: itemPositionsListener,
+              itemBuilder: (context, index) => SizedBox(
+                height: itemHeight,
+                child: Text('Item $index'),
+              ),
+              separatorBuilder: (context, index) => SizedBox(
+                height: separatorHeight,
+                child: Text('Separator $index'),
+              ),
+            );
+          },
         ),
       ),
     );

packages/stream_chat_flutter/test/scrollable_positioned_list/seperated_horizontal_scrollable_positioned_list_test.dart

@@ -2,10 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
-
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:pedantic/pedantic.dart';
 import 'package:stream_chat_flutter/scrollable_positioned_list/scrollable_positioned_list.dart';
 
 const screenHeight = 400.0;

packages/stream_chat_flutter/test/scrollable_positioned_list/shrink_wrap_position_list_test.dart

@@ -0,0 +1,473 @@
+// Copyright 2019 The Fuchsia 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 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:stream_chat_flutter/scrollable_positioned_list/scrollable_positioned_list.dart';
+import 'package:stream_chat_flutter/scrollable_positioned_list/src/item_positions_notifier.dart';
+import 'package:stream_chat_flutter/scrollable_positioned_list/src/positioned_list.dart';
+
+const screenHeight = 400.0;
+const screenWidth = 400.0;
+const itemHeight = screenHeight / 10.0;
+const defaultItemCount = 500;
+
+void main() {
+  final itemPositionsNotifier = ItemPositionsListener.create();
+
+  Future<void> setUpWidgetTest(
+    WidgetTester tester, {
+    int topItem = 0,
+    Key? key,
+    ScrollController? scrollController,
+    double anchor = 0,
+    int itemCount = defaultItemCount,
+    bool reverse = false,
+  }) async {
+    tester.binding.window.devicePixelRatioTestValue = 1.0;
+    tester.binding.window.physicalSizeTestValue =
+        const Size(screenWidth, screenHeight);
+
+    await tester.pumpWidget(
+      MaterialApp(
+        // Use flex layout to ensure that the minimum height is not limited to screenHeight
+        home: Column(children: [
+          // Use Constrained to make max height not more than screenHeight
+          ConstrainedBox(
+            constraints:
+                const BoxConstraints(maxHeight: screenHeight, maxWidth: screenWidth),
+            child: PositionedList(
+              key: key,
+              itemCount: itemCount,
+              positionedIndex: topItem,
+              alignment: anchor,
+              controller: scrollController,
+              itemBuilder: (context, index) => SizedBox(
+                height: itemHeight,
+                child: Text('Item $index'),
+              ),
+              itemPositionsNotifier:
+                  itemPositionsNotifier as ItemPositionsNotifier,
+              shrinkWrap: true,
+              reverse: reverse,
+            ),
+          ),
+        ]),
+      ),
+    );
+  }
+
+  testWidgets('short list with shrink wrap', (WidgetTester tester) async {
+    const itemCount = 5;
+    const key = Key('short_list');
+    await setUpWidgetTest(tester, itemCount: itemCount, key: key);
+    await tester.pump();
+
+    expect(
+        tester.getBottomRight(find.text('Item 4')).dy, itemHeight * itemCount);
+    expect(find.text('Item 4'), findsOneWidget);
+    expect(find.text('Item 5'), findsNothing);
+
+    final positionList = find.byKey(key);
+    expect(tester.getBottomRight(positionList).dy, itemHeight * itemCount);
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 0)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 4)
+            .itemTrailingEdge,
+        1.0);
+  });
+
+  testWidgets('List positioned with 0 at top and shrink wrap',
+      (WidgetTester tester) async {
+    await setUpWidgetTest(tester);
+    await tester.pump();
+
+    expect(find.text('Item 0'), findsOneWidget);
+    expect(find.text('Item 9'), findsOneWidget);
+    expect(find.text('Item 10'), findsNothing);
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 0)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 9)
+            .itemTrailingEdge,
+        1);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 10)
+            .itemLeadingEdge,
+        1);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 10)
+            .itemTrailingEdge,
+        11 / 10);
+  });
+
+  testWidgets('List positioned with 5 at top and shrink wrap',
+      (WidgetTester tester) async {
+    await setUpWidgetTest(tester, topItem: 5);
+    await tester.pump();
+
+    expect(find.text('Item 4'), findsNothing);
+    expect(find.text('Item 5'), findsOneWidget);
+    expect(find.text('Item 14'), findsOneWidget);
+    expect(find.text('Item 15'), findsNothing);
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 4)
+            .itemLeadingEdge,
+        -1 / 10);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 4)
+            .itemTrailingEdge,
+        0);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 5)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 14)
+            .itemTrailingEdge,
+        1);
+  });
+
+  testWidgets('List positioned with 20 at bottom and shrink wrap',
+      (WidgetTester tester) async {
+    await setUpWidgetTest(tester, topItem: 20, anchor: 1);
+    await tester.pump();
+
+    expect(find.text('Item 20'), findsNothing);
+    expect(find.text('Item 19'), findsOneWidget);
+    expect(find.text('Item 10'), findsOneWidget);
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 10)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 19)
+            .itemLeadingEdge,
+        9 / 10);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 19)
+            .itemTrailingEdge,
+        1);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 20)
+            .itemLeadingEdge,
+        1);
+  });
+
+  testWidgets('List positioned with 20 at halfway and shrink wrap',
+      (WidgetTester tester) async {
+    await setUpWidgetTest(tester, topItem: 20, anchor: 0.5);
+    await tester.pump();
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 20)
+            .itemLeadingEdge,
+        0.5);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 20)
+            .itemTrailingEdge,
+        0.5 + itemHeight / screenHeight);
+  });
+
+  testWidgets('List positioned with 20 half off top of screen and shrink wrap',
+      (WidgetTester tester) async {
+    await setUpWidgetTest(tester,
+        topItem: 20, anchor: -(itemHeight / screenHeight) / 2);
+    await tester.pump();
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 20)
+            .itemLeadingEdge,
+        -(itemHeight / screenHeight) / 2);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 20)
+            .itemTrailingEdge,
+        (itemHeight / screenHeight) / 2);
+  });
+
+  testWidgets('List positioned with 5 at top then scroll up 2 and shrink wrap',
+      (WidgetTester tester) async {
+    await setUpWidgetTest(tester, topItem: 5);
+
+    await tester.drag(
+        find.byType(PositionedList), const Offset(0, itemHeight * 2));
+    await tester.pump();
+
+    expect(find.text('Item 2'), findsNothing);
+    expect(find.text('Item 3'), findsOneWidget);
+    expect(find.text('Item 12'), findsOneWidget);
+    expect(find.text('Item 13'), findsNothing);
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 2)
+            .itemLeadingEdge,
+        -1 / 10);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 3)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 12)
+            .itemTrailingEdge,
+        1);
+  });
+
+  testWidgets(
+      'List positioned with 5 at top then scroll down 1/2 and shrink wrap',
+      (WidgetTester tester) async {
+    await setUpWidgetTest(tester, topItem: 5);
+
+    await tester.drag(
+        find.byType(PositionedList), const Offset(0, -1 / 2 * itemHeight));
+    await tester.pump();
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 5)
+            .itemTrailingEdge,
+        1 / 20);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 14)
+            .itemLeadingEdge,
+        17 / 20);
+  });
+
+  testWidgets('List positioned with 0 at top scroll up 5 and shrink wrap',
+      (WidgetTester tester) async {
+    final scrollController = ScrollController();
+    await setUpWidgetTest(tester, scrollController: scrollController);
+    await tester.pump();
+
+    scrollController.jumpTo(itemHeight * 5);
+    await tester.pump();
+    await tester.pumpAndSettle();
+
+    expect(find.text('Item 4'), findsNothing);
+    expect(find.text('Item 5'), findsOneWidget);
+    expect(find.text('Item 14'), findsOneWidget);
+    expect(find.text('Item 15'), findsNothing);
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 5)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 4)
+            .itemLeadingEdge,
+        -1 / 10);
+  });
+
+  testWidgets(
+      'List positioned with 5 at top then scroll up 2 programatically and shrink wrap',
+      (WidgetTester tester) async {
+    final scrollController = ScrollController();
+    await setUpWidgetTest(tester,
+        topItem: 5, scrollController: scrollController);
+
+    scrollController.jumpTo(-2 * itemHeight);
+    await tester.pump();
+
+    expect(find.text('Item 2'), findsNothing);
+    expect(find.text('Item 3'), findsOneWidget);
+    expect(find.text('Item 12'), findsOneWidget);
+    expect(find.text('Item 13'), findsNothing);
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 2)
+            .itemLeadingEdge,
+        -1 / 10);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 3)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 12)
+            .itemTrailingEdge,
+        1);
+  });
+
+  testWidgets(
+      'List positioned with 5 at top then scroll down 20 programatically and shrink wrap',
+      (WidgetTester tester) async {
+    final scrollController = ScrollController();
+    await setUpWidgetTest(tester,
+        topItem: 5, scrollController: scrollController);
+
+    scrollController.jumpTo(itemHeight * 20);
+    await tester.pump();
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 23)
+            .itemLeadingEdge,
+        -2 / 10);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 24)
+            .itemLeadingEdge,
+        -1 / 10);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 25)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 4)
+            .itemLeadingEdge,
+        -21 / 10);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 5)
+            .itemLeadingEdge,
+        -20 / 10);
+  });
+
+  testWidgets(
+      'List positioned with 5 at top and initial scroll offset and shrink wrap',
+      (WidgetTester tester) async {
+    final scrollController =
+        ScrollController(initialScrollOffset: -2 * itemHeight);
+    await setUpWidgetTest(tester,
+        topItem: 5, scrollController: scrollController);
+
+    expect(find.text('Item 2'), findsNothing);
+    expect(find.text('Item 3'), findsOneWidget);
+    expect(find.text('Item 12'), findsOneWidget);
+    expect(find.text('Item 13'), findsNothing);
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 3)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 12)
+            .itemTrailingEdge,
+        1);
+  });
+
+  testWidgets('short List with reverse and shrink wrap',
+      (WidgetTester tester) async {
+    const itemCount = 5;
+    const key = Key('short_list');
+    await setUpWidgetTest(tester,
+        itemCount: itemCount, key: key, reverse: true);
+    await tester.pump();
+
+    expect(find.text('Item 4'), findsOneWidget);
+    expect(find.text('Item 5'), findsNothing);
+    expect(
+        tester.getBottomRight(find.text('Item 0')).dy, itemHeight * itemCount);
+    expect(tester.getTopLeft(find.text('Item 4')).dy, 0);
+
+    final positionList = find.byKey(key);
+    expect(tester.getBottomRight(positionList).dy, itemHeight * itemCount);
+    expect(tester.getTopLeft(positionList).dy, 0);
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 0)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 4)
+            .itemTrailingEdge,
+        1.0);
+  });
+
+  testWidgets('test nested positioned list', (WidgetTester tester) async {
+    const itemCount = 50;
+    const key = Key('short_list');
+    tester.binding.window.devicePixelRatioTestValue = 1.0;
+    tester.binding.window.physicalSizeTestValue =
+        const Size(screenWidth, screenHeight);
+
+    await tester.pumpWidget(
+      MaterialApp(
+        // Use flex layout to ensure that the minimum height is not limited to screenHeight
+        home: PositionedList(
+          itemCount: 5,
+          itemBuilder: (context, index) {
+            if (index == 0) {
+              return PositionedList(
+                  key: key,
+                  itemCount: itemCount,
+                  shrinkWrap: true,
+                  itemBuilder: (context, idx) => SizedBox(
+                        height: itemHeight,
+                        child: Text('Item $idx'),
+                      ));
+            } else {
+              return SizedBox(
+                height: itemHeight,
+                child: Text('Item ${itemCount + index - 1}'),
+              );
+            }
+          },
+          itemPositionsNotifier: itemPositionsNotifier as ItemPositionsNotifier,
+        ),
+      ),
+    );
+    await tester.pump();
+
+    expect(find.text('Item 0'), findsOneWidget);
+    expect(find.text('Item 50'), findsNothing);
+    expect(tester.getTopLeft(find.text('Item 0')).dy, 0);
+    expect(tester.getBottomRight(find.text('Item 9')).dy, screenHeight);
+
+    final positionList = find.byKey(key);
+    expect(tester.getBottomRight(positionList).dy, itemHeight * itemCount);
+    expect(tester.getTopLeft(positionList).dy, 0);
+
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 0)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsNotifier.itemPositions.value
+            .firstWhere((position) => position.index == 0)
+            .itemTrailingEdge,
+        5.0);
+  });
+}

packages/stream_chat_flutter/test/scrollable_positioned_list/shrink_wrap_scrollable_position_list_test.dart

@@ -0,0 +1,246 @@
+// Copyright 2019 The Fuchsia 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 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:pedantic/pedantic.dart';
+import 'package:stream_chat_flutter/scrollable_positioned_list/scrollable_positioned_list.dart';
+
+const screenHeight = 400.0;
+const screenWidth = 400.0;
+const itemHeight = screenHeight / 10.0;
+const itemCount = 500;
+const scrollDuration = Duration(seconds: 1);
+
+void main() {
+  Future<void> setUpWidgetTest(
+    WidgetTester tester, {
+    ItemScrollController? itemScrollController,
+    ItemPositionsListener? itemPositionsListener,
+    EdgeInsets? padding,
+    int initialIndex = 0,
+  }) async {
+    tester.binding.window.devicePixelRatioTestValue = 1.0;
+    tester.binding.window.physicalSizeTestValue =
+        const Size(screenWidth, screenHeight);
+
+    await tester.pumpWidget(
+      MaterialApp(
+        // Use flex layout to ensure that the minimum height is not limited to screenHeight
+        home: Column(children: [
+          // Use Constrained to make max height not more than screenHeight
+          ConstrainedBox(
+            constraints:
+                const BoxConstraints(maxHeight: screenHeight, maxWidth: screenWidth),
+            child: ScrollablePositionedList.builder(
+              itemCount: itemCount,
+              initialScrollIndex: initialIndex,
+              itemScrollController: itemScrollController,
+              itemBuilder: (context, index) => SizedBox(
+                height: itemHeight,
+                child: Text('Item $index'),
+              ),
+              itemPositionsListener: itemPositionsListener,
+              shrinkWrap: true,
+              padding: padding,
+            ),
+          ),
+        ]),
+      ),
+    );
+  }
+
+  testWidgets('List positioned with 0 at top and shrink wrap',
+      (WidgetTester tester) async {
+    final itemPositionsListener = ItemPositionsListener.create();
+    await setUpWidgetTest(tester, itemPositionsListener: itemPositionsListener);
+
+    expect(tester.getTopLeft(find.text('Item 0')).dy, 0);
+    expect(tester.getBottomRight(find.text('Item 9')).dy, screenHeight);
+    expect(find.text('Item 10'), findsNothing);
+
+    expect(
+        itemPositionsListener.itemPositions.value
+            .firstWhere((position) => position.index == 0)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsListener.itemPositions.value
+            .firstWhere((position) => position.index == 9)
+            .itemTrailingEdge,
+        1);
+  });
+
+  testWidgets('Scroll to 1 then 2 (both already on screen) with shrink wrap',
+      (WidgetTester tester) async {
+    final itemScrollController = ItemScrollController();
+    final itemPositionsListener = ItemPositionsListener.create();
+    await setUpWidgetTest(tester,
+        itemScrollController: itemScrollController,
+        itemPositionsListener: itemPositionsListener);
+
+    unawaited(
+        itemScrollController.scrollTo(index: 1, duration: scrollDuration));
+    await tester.pump();
+    await tester.pump(scrollDuration);
+    expect(find.text('Item 0'), findsNothing);
+    expect(
+        itemPositionsListener.itemPositions.value
+            .firstWhere((position) => position.index == 1)
+            .itemLeadingEdge,
+        0);
+    expect(tester.getTopLeft(find.text('Item 1')).dy, 0);
+
+    unawaited(
+        itemScrollController.scrollTo(index: 2, duration: scrollDuration));
+    await tester.pump();
+    await tester.pump(scrollDuration);
+
+    expect(find.text('Item 1'), findsNothing);
+    expect(tester.getTopLeft(find.text('Item 2')).dy, 0);
+
+    expect(
+        itemPositionsListener.itemPositions.value
+            .firstWhere((position) => position.index == 2)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsListener.itemPositions.value
+            .firstWhere((position) => position.index == 11)
+            .itemTrailingEdge,
+        1);
+  });
+
+  testWidgets(
+      'Scroll to 5 (already on screen) and then back to 0 with shrink wrap',
+      (WidgetTester tester) async {
+    final itemScrollController = ItemScrollController();
+    final itemPositionsListener = ItemPositionsListener.create();
+    await setUpWidgetTest(tester,
+        itemScrollController: itemScrollController,
+        itemPositionsListener: itemPositionsListener);
+
+    unawaited(
+        itemScrollController.scrollTo(index: 5, duration: scrollDuration));
+    await tester.pumpAndSettle();
+    unawaited(
+        itemScrollController.scrollTo(index: 0, duration: scrollDuration));
+    await tester.pumpAndSettle();
+
+    expect(find.text('Item 0'), findsOneWidget);
+    expect(find.text('Item 9'), findsOneWidget);
+    expect(find.text('Item 10'), findsNothing);
+
+    expect(
+        itemPositionsListener.itemPositions.value
+            .firstWhere((position) => position.index == 0)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsListener.itemPositions.value
+            .firstWhere((position) => position.index == 9)
+            .itemTrailingEdge,
+        1);
+  });
+
+  testWidgets('Scroll to 100 (not already on screen) with shrink wrap',
+      (WidgetTester tester) async {
+    final itemScrollController = ItemScrollController();
+    final itemPositionsListener = ItemPositionsListener.create();
+    await setUpWidgetTest(tester,
+        itemScrollController: itemScrollController,
+        itemPositionsListener: itemPositionsListener);
+
+    unawaited(
+        itemScrollController.scrollTo(index: 100, duration: scrollDuration));
+    await tester.pumpAndSettle();
+
+    expect(find.text('Item 99'), findsNothing);
+    expect(find.text('Item 100'), findsOneWidget);
+
+    expect(
+        itemPositionsListener.itemPositions.value
+            .firstWhere((position) => position.index == 100)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsListener.itemPositions.value
+            .firstWhere((position) => position.index == 109)
+            .itemTrailingEdge,
+        1);
+  });
+
+  testWidgets('Jump to 100 with shrink wrap', (WidgetTester tester) async {
+    final itemScrollController = ItemScrollController();
+    final itemPositionsListener = ItemPositionsListener.create();
+    await setUpWidgetTest(tester,
+        itemScrollController: itemScrollController,
+        itemPositionsListener: itemPositionsListener);
+
+    itemScrollController.jumpTo(index: 100);
+    await tester.pumpAndSettle();
+
+    expect(tester.getTopLeft(find.text('Item 100')).dy, 0);
+    expect(tester.getBottomRight(find.text('Item 109')).dy, screenHeight);
+
+    expect(
+        itemPositionsListener.itemPositions.value
+            .firstWhere((position) => position.index == 100)
+            .itemLeadingEdge,
+        0);
+    expect(
+        itemPositionsListener.itemPositions.value
+            .firstWhere((position) => position.index == 109)
+            .itemTrailingEdge,
+        1);
+  });
+
+  testWidgets('padding test - centered sliver at bottom with shrink wrap',
+      (WidgetTester tester) async {
+    final itemScrollController = ItemScrollController();
+    await setUpWidgetTest(
+      tester,
+      itemScrollController: itemScrollController,
+      padding: const EdgeInsets.all(10),
+    );
+
+    expect(tester.getTopLeft(find.text('Item 0')), const Offset(10, 10));
+    expect(tester.getTopLeft(find.text('Item 1')),
+        const Offset(10, itemHeight + 10));
+    expect(tester.getBottomRight(find.text('Item 1')),
+        const Offset(screenWidth - 10, 10 + itemHeight * 2));
+
+    unawaited(
+        itemScrollController.scrollTo(index: 490, duration: scrollDuration));
+    await tester.pumpAndSettle();
+
+    await tester.drag(
+        find.byType(ScrollablePositionedList), const Offset(0, -100));
+    await tester.pumpAndSettle();
+
+    expect(tester.getTopLeft(find.text('Item 499')),
+        const Offset(10, screenHeight - itemHeight - 10));
+  });
+
+  testWidgets('padding test - centered sliver not at bottom',
+      (WidgetTester tester) async {
+    final itemScrollController = ItemScrollController();
+    await setUpWidgetTest(
+      tester,
+      itemScrollController: itemScrollController,
+      initialIndex: 2,
+      padding: const EdgeInsets.all(10),
+    );
+
+    await tester.drag(
+        find.byType(ScrollablePositionedList), const Offset(0, 200));
+    await tester.pumpAndSettle();
+
+    expect(tester.getTopLeft(find.text('Item 0')), const Offset(10, 10));
+    expect(tester.getTopLeft(find.text('Item 2')),
+        const Offset(10, 10 + itemHeight * 2));
+    expect(tester.getTopLeft(find.text('Item 3')),
+        const Offset(10, 10 + itemHeight * 3));
+  });
+}