fix: derive Android Maestro scroll viewport

Author: thymikee

src/compat/maestro/__tests__/runtime-port-geometry.test.ts

@@ -137,6 +137,36 @@ test('excludes an in-viewport Android scrollable that is hidden from the user',
   });
 });
 
+test('derives an Android viewport from visible scroll containers when roots are omitted', () => {
+  const snapshot = {
+    createdAt: 0,
+    nodes: [
+      {
+        index: 0,
+        ref: '@e1',
+        type: 'android.widget.ScrollView',
+        visibleToUser: true,
+        rect: { x: 0, y: 0, width: 1344, height: 2992 },
+      },
+      {
+        index: 1,
+        ref: '@e2',
+        parentIndex: 0,
+        type: 'android.widget.ScrollView',
+        visibleToUser: true,
+        rect: { x: 54, y: 159, width: 1236, height: 2449 },
+      },
+    ],
+  };
+
+  expect(
+    resolveMaestroScrollableGesture(snapshot, { id: 'home-open-form' }, 'down', 600, 'android'),
+  ).toEqual({
+    gesture: { from: { x: 672, y: 1496 }, to: { x: 672, y: 299 }, durationMs: 600 },
+    viewport: { x: 0, y: 0, width: 1344, height: 2992 },
+  });
+});
+
 test('does not associate a selector in an Android hidden scroll subtree', () => {
   const snapshot = {
     createdAt: 0,

src/compat/maestro/runtime-port-geometry.ts

@@ -62,14 +62,15 @@ function selectMaestroScrollableViewport(
   direction: MaestroDirection,
   platform: MaestroPlatform,
 ): Rect | undefined {
-  const applicationViewport = findLargestViewportRect(snapshot.nodes);
-  if (!applicationViewport || !isPositiveFiniteRect(applicationViewport)) return undefined;
   const vertical = direction === 'up' || direction === 'down';
   const scrollable = filterVisibleMaestroMatches({
     nodes: snapshot.nodes,
     matches: snapshot.nodes.filter((node) => isScrollableSnapshotType(node.type)),
     platform,
   });
+  const applicationViewport =
+    findLargestViewportRect(snapshot.nodes) ?? findLargestPositiveRect(scrollable);
+  if (!applicationViewport || !isPositiveFiniteRect(applicationViewport)) return undefined;
   const candidates = scrollable.flatMap((node) => {
     if (!isPositiveFiniteRect(node.rect)) return [];
     const viewport = intersectRects(node.rect, applicationViewport);
@@ -95,6 +96,21 @@ function selectMaestroScrollableViewport(
   return candidates.sort(compareViewportAreaDescending)[0]?.viewport;
 }
 
+function findLargestPositiveRect(
+  nodes: readonly SnapshotState['nodes'][number][],
+): Rect | undefined {
+  let largest: Rect | undefined;
+  for (const node of nodes) {
+    if (
+      isPositiveFiniteRect(node.rect) &&
+      (!largest || node.rect.width * node.rect.height > largest.width * largest.height)
+    ) {
+      largest = node.rect;
+    }
+  }
+  return largest;
+}
+
 function intersectRects(left: Rect, right: Rect): Rect | undefined {
   const x = Math.max(left.x, right.x);
   const y = Math.max(left.y, right.y);