Enhance drag functionality to directly use Scrollable as dragStart in…

lib/src/act/act.dart

@@ -270,10 +270,13 @@ class Act {
     final dragStartSnapshot = dragStart.snapshot()..existsOnce();
     _detectSizeZero(snapshot: dragStartSnapshot);
 
-    // Take the closest Scrollable above the dragStart widget. This is the
-    // widget which makes a widget scrollable. It must always exist.
-    final WidgetSelector<Scrollable> scrollable =
-        spot<Scrollable>().withChild(dragStart).last();
+    final WidgetSelector<Scrollable> scrollable = () {
+      final element = dragStartSnapshot.discoveredElement!;
+      if (element.widget is Scrollable) {
+        return spotElement<Scrollable>(element);
+      }
+      return spot<Scrollable>().withChild(dragStart).last();
+    }();
 
     // Save the 'Element' of the currently targeted Scrollable.
     // This ensures that—even if multiple scrollables exist or the

test/act/act_drag_test.dart

@@ -1,4 +1,3 @@
-import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:spot/spot.dart';
@@ -120,6 +119,56 @@ void dragTests() {
         await act.tap(secondItem);
       },
     );
+
+    testWidgets(
+      'Finds widget in vertical ListView after dragging when dragStart is a Scrollable',
+      (tester) async {
+        await tester.pumpWidget(
+          const DragUntilVisibleSingleDirectionTestWidget(
+            axis: Axis.vertical,
+            ignorePointerAtIndices: [0, 1, 2, 3, 4, 5, 6, 7, 8],
+          ),
+        );
+
+        final firstItem = spot<DragUntilVisibleSingleDirectionTestWidget>()
+            .spot<Scrollable>()
+            .last()
+          ..existsOnce();
+        final secondItem = spotText('Item at index: 27', exact: true)
+          ..doesNotExist();
+        await act.dragUntilVisible(
+          dragStart: firstItem,
+          dragTarget: secondItem,
+          maxIteration: 30,
+        );
+        secondItem.existsOnce();
+      },
+    );
+
+    testWidgets(
+      'Finds widget after dragging when a keyed dragStart resolves to a Scrollable',
+      (tester) async {
+        const scrollableKey = ValueKey('direct-scrollable');
+        await tester.pumpWidget(
+          const DragUntilVisibleSingleDirectionTestWidget(
+            axis: Axis.vertical,
+            ignorePointerAtIndices: [0, 1, 2, 3, 4, 5, 6, 7, 8],
+            scrollableKey: scrollableKey,
+          ),
+        );
+
+        final firstItem = spotKey(scrollableKey)..existsOnce();
+        expect(firstItem.snapshotWidget(), isA<Scrollable>());
+        final secondItem = spotText('Item at index: 27', exact: true)
+          ..doesNotExist();
+        await act.dragUntilVisible(
+          dragStart: firstItem,
+          dragTarget: secondItem,
+          maxIteration: 30,
+        );
+        secondItem.existsOnce();
+      },
+    );
   });
 
   group('Horizontal Drag', () {

test/timeline/drag/drag_until_visible_test_widget.dart

@@ -7,11 +7,13 @@ class DragUntilVisibleSingleDirectionTestWidget extends StatelessWidget {
     required this.axis,
     this.ignorePointerAtIndices = const [0, 0],
     this.useColumnOrRow = false,
+    this.scrollableKey,
   });
 
   final Axis axis;
   final List<int> ignorePointerAtIndices;
   final bool useColumnOrRow;
+  final Key? scrollableKey;
 
   @override
   Widget build(BuildContext context) {
@@ -31,6 +33,23 @@ class DragUntilVisibleSingleDirectionTestWidget extends StatelessWidget {
     );
 
     final child = () {
+      if (scrollableKey != null) {
+        return Scrollable(
+          key: scrollableKey,
+          viewportBuilder: (context, position) {
+            return Viewport(
+              axisDirection: _axisDirection(axis),
+              offset: position,
+              slivers: [
+                SliverFixedExtentList(
+                  itemExtent: 100,
+                  delegate: SliverChildListDelegate(items),
+                ),
+              ],
+            );
+          },
+        );
+      }
       if (useColumnOrRow) {
         return SingleChildScrollView(
           scrollDirection: axis,
@@ -78,6 +97,13 @@ class DragUntilVisibleSingleDirectionTestWidget extends StatelessWidget {
   }
 }
 
+AxisDirection _axisDirection(Axis axis) {
+  if (axis == Axis.vertical) {
+    return AxisDirection.down;
+  }
+  return AxisDirection.right;
+}
+
 class NestedScrollDragUntilVisibleTestWidget extends StatelessWidget {
   const NestedScrollDragUntilVisibleTestWidget({
     super.key,