stabilize the way we navigate multiple pages for E2E macrobenchmarks (#96157)

dev/benchmarks/macrobenchmarks/lib/common.dart

@@ -34,5 +34,6 @@ const String kOpacityPeepholeOpacityOfColOfRowsRouteName = '$kOpacityPeepholeRou
 const String kOpacityPeepholeFadeTransitionTextRouteName = '$kOpacityPeepholeRouteName/fade_transition_text';
 
 const String kScrollableName = '/macrobenchmark_listview';
+const String kOpacityScrollableName = '$kOpacityPeepholeRouteName/listview';
 
 const String kStackSizeKey = 'stack_size';

dev/benchmarks/macrobenchmarks/lib/src/opacity_peephole.dart

@@ -17,7 +17,7 @@ class OpacityPeepholePage extends StatelessWidget {
     return Scaffold(
       appBar: AppBar(title: const Text('Opacity Peephole tests')),
       body: ListView(
-        key: const Key('${kOpacityPeepholeRouteName}_listview'),
+        key: const Key(kOpacityScrollableName),
         children: <Widget>[
           for (OpacityPeepholeCase variant in allOpacityPeepholeCases)
             ElevatedButton(

dev/benchmarks/macrobenchmarks/test/opacity_peephole_col_of_rows_perf_e2e.dart

@@ -7,9 +7,12 @@ import 'package:macrobenchmarks/common.dart';
 import 'util.dart';
 
 void main() {
-  macroPerfTestE2E(
+  macroPerfTestMultiPageE2E(
     'opacity_peephole_col_of_rows_perf',
-    kOpacityPeepholeOpacityOfColOfRowsRouteName,
+    <ScrollableButtonRoute>[
+      ScrollableButtonRoute(kScrollableName, kOpacityPeepholeRouteName),
+      ScrollableButtonRoute(kOpacityScrollableName, kOpacityPeepholeOpacityOfColOfRowsRouteName)
+    ],
     pageDelay: const Duration(seconds: 1),
     duration: const Duration(seconds: 10),
   );

dev/benchmarks/macrobenchmarks/test/opacity_peephole_fade_transition_text_perf_e2e.dart

@@ -7,9 +7,12 @@ import 'package:macrobenchmarks/common.dart';
 import 'util.dart';
 
 void main() {
-  macroPerfTestE2E(
+  macroPerfTestMultiPageE2E(
     'opacity_peephole_fade_transition_text_perf',
-    kOpacityPeepholeFadeTransitionTextRouteName,
+    <ScrollableButtonRoute>[
+      ScrollableButtonRoute(kScrollableName, kOpacityPeepholeRouteName),
+      ScrollableButtonRoute(kOpacityScrollableName, kOpacityPeepholeFadeTransitionTextRouteName)
+    ],
     pageDelay: const Duration(seconds: 1),
     duration: const Duration(seconds: 10),
   );

dev/benchmarks/macrobenchmarks/test/opacity_peephole_grid_of_opacity_perf_e2e.dart

@@ -7,9 +7,12 @@ import 'package:macrobenchmarks/common.dart';
 import 'util.dart';
 
 void main() {
-  macroPerfTestE2E(
+  macroPerfTestMultiPageE2E(
     'opacity_peephole_grid_of_opacity_perf',
-    kOpacityPeepholeGridOfOpacityRouteName,
+    <ScrollableButtonRoute>[
+      ScrollableButtonRoute(kScrollableName, kOpacityPeepholeRouteName),
+      ScrollableButtonRoute(kOpacityScrollableName, kOpacityPeepholeGridOfOpacityRouteName)
+    ],
     pageDelay: const Duration(seconds: 1),
     duration: const Duration(seconds: 10),
   );

dev/benchmarks/macrobenchmarks/test/opacity_peephole_one_rect_perf_e2e.dart

@@ -7,9 +7,12 @@ import 'package:macrobenchmarks/common.dart';
 import 'util.dart';
 
 void main() {
-  macroPerfTestE2E(
+  macroPerfTestMultiPageE2E(
     'opacity_peephole_one_rect_perf',
-    kOpacityPeepholeOneRectRouteName,
+    <ScrollableButtonRoute>[
+      ScrollableButtonRoute(kScrollableName, kOpacityPeepholeRouteName),
+      ScrollableButtonRoute(kOpacityScrollableName, kOpacityPeepholeOneRectRouteName)
+    ],
     pageDelay: const Duration(seconds: 1),
     duration: const Duration(seconds: 10),
   );

dev/benchmarks/macrobenchmarks/test/opacity_peephole_opacity_of_grid_perf_e2e.dart

@@ -7,9 +7,12 @@ import 'package:macrobenchmarks/common.dart';
 import 'util.dart';
 
 void main() {
-  macroPerfTestE2E(
+  macroPerfTestMultiPageE2E(
     'opacity_peephole_opacity_of_grid_perf',
-    kOpacityPeepholeOpacityOfGridRouteName,
+    <ScrollableButtonRoute>[
+      ScrollableButtonRoute(kScrollableName, kOpacityPeepholeRouteName),
+      ScrollableButtonRoute(kOpacityScrollableName, kOpacityPeepholeOpacityOfGridRouteName)
+    ],
     pageDelay: const Duration(seconds: 1),
     duration: const Duration(seconds: 10),
   );

dev/benchmarks/macrobenchmarks/test/util.dart

@@ -5,10 +5,18 @@
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:integration_test/integration_test.dart';
+import 'package:macrobenchmarks/common.dart';
 import 'package:macrobenchmarks/main.dart' as app;
 
 typedef ControlCallback = Future<void> Function(WidgetController controller);
 
+class ScrollableButtonRoute {
+  ScrollableButtonRoute(this.listViewKey, this.buttonKey);
+
+  final String listViewKey;
+  final String buttonKey;
+}
+
 void macroPerfTestE2E(
   String testName,
   String routeName, {
@@ -17,6 +25,19 @@ void macroPerfTestE2E(
   ControlCallback? body,
   ControlCallback? setup,
 }) {
+  macroPerfTestMultiPageE2E(testName, <ScrollableButtonRoute>[
+    ScrollableButtonRoute(kScrollableName, routeName),
+  ]);
+}
+
+void macroPerfTestMultiPageE2E(
+    String testName,
+    List<ScrollableButtonRoute> routes, {
+      Duration? pageDelay,
+      Duration duration = const Duration(seconds: 3),
+      ControlCallback? body,
+      ControlCallback? setup,
+    }) {
   final WidgetsBinding _binding = IntegrationTestWidgetsFlutterBinding.ensureInitialized();
   assert(_binding is IntegrationTestWidgetsFlutterBinding);
   final IntegrationTestWidgetsFlutterBinding binding = _binding as IntegrationTestWidgetsFlutterBinding;
@@ -33,16 +54,26 @@ void macroPerfTestE2E(
     // See: https://github.com/flutter/flutter/issues/19434
     await tester.binding.delayed(const Duration(microseconds: 250));
 
-    expect(routeName, startsWith('/'));
-    int i = 0;
-    while (i < routeName.length) {
-      i = routeName.indexOf('/', i + 1);
-      if (i < 0) {
-        i = routeName.length;
-      }
-      final Finder button = find.byKey(ValueKey<String>(routeName.substring(0, i)), skipOffstage: false);
-      await tester.scrollUntilVisible(button, 50);
+    for (final ScrollableButtonRoute route in routes) {
+      expect(route.listViewKey, startsWith('/'));
+      expect(route.buttonKey, startsWith('/'));
+
+      // Make sure each list view page is settled
+      await tester.pumpAndSettle();
+
+      final Finder listView = find.byKey(ValueKey<String>(route.listViewKey));
+      // ListView is not a Scrollable, but it contains one
+      final Finder scrollable = find.descendant(of: listView, matching: find.byType(Scrollable));
+      // scrollable should find one widget as soon as the page is loaded
+      expect(scrollable, findsOneWidget);
+
+      final Finder button = find.byKey(ValueKey<String>(route.buttonKey), skipOffstage: false);
+      // button may or may not find a widget right away until we scroll to it
+      await tester.scrollUntilVisible(button, 50, scrollable: scrollable);
+      // After scrolling, button should find one Widget
       expect(button, findsOneWidget);
+
+      // Allow scrolling to settle
       await tester.pumpAndSettle();
       await tester.tap(button);
       // Cannot be pumpAndSettle because some tests have infinite animation.