Update `ToggleButtons`, `ExpansionPanel`, and `ExpandIcon` tests for Material 3 (#141868)

Updated unit tests for `ToggleButtons`, `ExpansionPanel`, and `ExpandIcon` to have M2 and M3 versions.

More info in #139076

packages/flutter/test/material/expand_icon_test.dart

@@ -73,9 +73,9 @@ void main() {
     expect(iconTheme.data.color, equals(Colors.white60));
   });
 
-  testWidgets('ExpandIcon disabled', (WidgetTester tester) async {
+  testWidgets('Material2 - ExpandIcon disabled', (WidgetTester tester) async {
     IconTheme iconTheme;
-    // Light mode test
+    // Test light mode.
     await tester.pumpWidget(wrap(
       theme: ThemeData(useMaterial3: false),
       child: const ExpandIcon(onPressed: null),
@@ -85,7 +85,7 @@ void main() {
     iconTheme = tester.firstWidget(find.byType(IconTheme).last);
     expect(iconTheme.data.color, equals(Colors.black38));
 
-    // Dark mode test
+    // Test dark mode.
     await tester.pumpWidget(wrap(
       child: const ExpandIcon(onPressed: null),
       theme: ThemeData(useMaterial3: false, brightness: Brightness.dark),
@@ -96,6 +96,37 @@ void main() {
     expect(iconTheme.data.color, equals(Colors.white38));
   });
 
+  testWidgets('Material3 - ExpandIcon disabled', (WidgetTester tester) async {
+    ThemeData theme = ThemeData();
+    IconTheme iconTheme;
+    // Test light mode.
+    await tester.pumpWidget(wrap(
+      theme: theme,
+      child: const ExpandIcon(onPressed: null),
+    ));
+    await tester.pumpAndSettle();
+
+    iconTheme = tester.firstWidget(find.byType(IconTheme).last);
+    expect(
+      iconTheme.data.color,
+      equals(theme.colorScheme.onSurface.withOpacity(0.38)),
+    );
+
+    theme = ThemeData(brightness: Brightness.dark);
+    // Test dark mode.
+    await tester.pumpWidget(wrap(
+      theme: theme,
+      child: const ExpandIcon(onPressed: null),
+    ));
+    await tester.pumpAndSettle();
+
+    iconTheme = tester.firstWidget(find.byType(IconTheme).last);
+    expect(
+      iconTheme.data.color,
+      equals(theme.colorScheme.onSurface.withOpacity(0.38)),
+    );
+  });
+
   testWidgets('ExpandIcon test isExpanded does not trigger callback', (WidgetTester tester) async {
     bool expanded = false;
 
@@ -173,7 +204,7 @@ void main() {
     expect(icon.size, 48);
   });
 
-  testWidgets('ExpandIcon has correct semantic hints', (WidgetTester tester) async {
+  testWidgets('Material2 - ExpandIcon has correct semantic hints', (WidgetTester tester) async {
     final SemanticsHandle handle = tester.ensureSemantics();
     const DefaultMaterialLocalizations localizations = DefaultMaterialLocalizations();
     await tester.pumpWidget(wrap(
@@ -194,6 +225,7 @@ void main() {
     ));
 
     await tester.pumpWidget(wrap(
+      theme: ThemeData(useMaterial3: false),
       child: ExpandIcon(
         onPressed: (bool _) { },
       ),
@@ -210,6 +242,52 @@ void main() {
     handle.dispose();
   });
 
+  testWidgets('Material3 - ExpandIcon has correct semantic hints', (WidgetTester tester) async {
+    final SemanticsHandle handle = tester.ensureSemantics();
+    const DefaultMaterialLocalizations localizations = DefaultMaterialLocalizations();
+
+    await tester.pumpWidget(wrap(
+      child: ExpandIcon(
+        isExpanded: true,
+        onPressed: (bool _) { },
+      ),
+    ));
+
+    expect(tester.getSemantics(find.byType(ExpandIcon)), matchesSemantics(
+      onTapHint: localizations.expandedIconTapHint,
+      children: <Matcher>[
+        matchesSemantics(
+          hasTapAction: true,
+          hasEnabledState: true,
+          isEnabled: true,
+          isFocusable: true,
+          isButton: true,
+        ),
+      ],
+    ));
+
+    await tester.pumpWidget(wrap(
+      child: ExpandIcon(
+        onPressed: (bool _) { },
+      ),
+    ));
+
+    expect(tester.getSemantics(find.byType(ExpandIcon)), matchesSemantics(
+      onTapHint: localizations.collapsedIconTapHint,
+      children: <Matcher>[
+        matchesSemantics(
+          hasTapAction: true,
+          hasEnabledState: true,
+          isEnabled: true,
+          isFocusable: true,
+          isButton: true,
+        ),
+      ],
+    ));
+
+    handle.dispose();
+  });
+
   testWidgets('ExpandIcon uses custom icon color and expanded icon color', (WidgetTester tester) async {
     bool expanded = false;
     IconTheme iconTheme;

packages/flutter/test/material/expansion_panel_test.dart

@@ -178,7 +178,7 @@ void main() {
     expect(box.size.height - oldHeight, greaterThanOrEqualTo(100.0)); // 100 + some margin
   });
 
-  testWidgets('ExpansionPanelList does not merge header when canTapOnHeader is false', (WidgetTester tester) async {
+  testWidgets('Material2 - ExpansionPanelList does not merge header when canTapOnHeader is false', (WidgetTester tester) async {
     final SemanticsHandle handle = tester.ensureSemantics();
     final Key headerKey = UniqueKey();
     await tester.pumpWidget(
@@ -226,6 +226,58 @@ void main() {
     handle.dispose();
   });
 
+  testWidgets('Material3 - ExpansionPanelList does not merge header when canTapOnHeader is false', (WidgetTester tester) async {
+    final SemanticsHandle handle = tester.ensureSemantics();
+    final Key headerKey = UniqueKey();
+    await tester.pumpWidget(
+      MaterialApp(
+        home: ExpansionPanelListSemanticsTest(headerKey: headerKey),
+      ),
+    );
+
+    // Make sure custom gesture detector widget is clickable.
+    await tester.tap(find.text('head1'));
+    await tester.pump();
+
+    final ExpansionPanelListSemanticsTestState state =
+      tester.state(find.byType(ExpansionPanelListSemanticsTest));
+    expect(state.headerTapped, true);
+
+    // Check the expansion icon semantics does not merged with header widget.
+    final Finder expansionIcon = find.descendant(
+      of: find.ancestor(
+        of: find.byKey(headerKey),
+        matching: find.byType(Row),
+      ),
+      matching: find.byType(ExpandIcon),
+    );
+
+    expect(tester.getSemantics(expansionIcon), matchesSemantics(
+      label: 'Expand',
+      children: <Matcher>[
+        matchesSemantics(
+          isButton: true,
+          hasEnabledState: true,
+          isEnabled: true,
+          isFocusable: true,
+          hasTapAction: true,
+        ),
+      ],
+    ));
+
+    // Check custom header widget semantics is preserved.
+    final Finder headerWidget = find.descendant(
+      of: find.byKey(headerKey),
+      matching: find.byType(RichText),
+    );
+    expect(tester.getSemantics(headerWidget), matchesSemantics(
+      label: 'head1',
+      hasTapAction: true,
+    ));
+
+    handle.dispose();
+  });
+
   testWidgets('Multiple Panel List test', (WidgetTester tester) async {
     await tester.pumpWidget(
       MaterialApp(
@@ -998,7 +1050,7 @@ void main() {
     await tester.pumpAndSettle();
   });
 
-  testWidgets('Panel header has semantics, canTapOnHeader = false ', (WidgetTester tester) async {
+  testWidgets('Material2 - Panel header has semantics, canTapOnHeader = false', (WidgetTester tester) async {
     const Key expandedKey = Key('expanded');
     const Key collapsedKey = Key('collapsed');
     const DefaultMaterialLocalizations localizations = DefaultMaterialLocalizations();
@@ -1083,6 +1135,99 @@ void main() {
     handle.dispose();
   });
 
+  testWidgets('Material3 - Panel header has semantics, canTapOnHeader = false', (WidgetTester tester) async {
+    const Key expandedKey = Key('expanded');
+    const Key collapsedKey = Key('collapsed');
+    const DefaultMaterialLocalizations localizations = DefaultMaterialLocalizations();
+    final SemanticsHandle handle = tester.ensureSemantics();
+    final List<ExpansionPanel> demoItems = <ExpansionPanel>[
+      ExpansionPanel(
+        headerBuilder: (BuildContext context, bool isExpanded) {
+          return const Text('Expanded', key: expandedKey);
+        },
+        body: const SizedBox(height: 100.0),
+        isExpanded: true,
+      ),
+      ExpansionPanel(
+        headerBuilder: (BuildContext context, bool isExpanded) {
+          return const Text('Collapsed', key: collapsedKey);
+        },
+        body: const SizedBox(height: 100.0),
+      ),
+    ];
+
+    final ExpansionPanelList expansionList = ExpansionPanelList(
+      children: demoItems,
+    );
+
+    await tester.pumpWidget(
+      MaterialApp(
+        home: SingleChildScrollView(
+          child: expansionList,
+        ),
+      ),
+    );
+
+    // Check the semantics of [ExpandIcon] for expanded panel.
+    final Finder expandedIcon = find.descendant(
+      of: find.ancestor(
+        of: find.byKey(expandedKey),
+        matching: find.byType(Row),
+      ),
+      matching: find.byType(ExpandIcon),
+    );
+
+    expect(tester.getSemantics(expandedIcon), matchesSemantics(
+      label: 'Collapse',
+      onTapHint: localizations.expandedIconTapHint,
+      children: <Matcher>[
+        matchesSemantics(
+          isButton: true,
+          hasEnabledState: true,
+          isEnabled: true,
+          isFocusable: true,
+          hasTapAction: true,
+        ),
+      ],
+    ));
+
+    // Check the semantics of the header widget for expanded panel.
+    final Finder expandedHeader = find.byKey(expandedKey);
+    expect(tester.getSemantics(expandedHeader), matchesSemantics(
+      label: 'Expanded',
+    ));
+
+    // Check the semantics of [ExpandIcon] for collapsed panel.
+    final Finder collapsedIcon = find.descendant(
+      of: find.ancestor(
+        of: find.byKey(collapsedKey),
+        matching: find.byType(Row),
+      ),
+      matching: find.byType(ExpandIcon),
+    );
+    expect(tester.getSemantics(collapsedIcon), matchesSemantics(
+      label: 'Expand',
+      onTapHint: localizations.collapsedIconTapHint,
+      children: <Matcher>[
+        matchesSemantics(
+          isButton: true,
+          hasEnabledState: true,
+          isEnabled: true,
+          isFocusable: true,
+          hasTapAction: true,
+        ),
+      ],
+    ));
+
+    // Check the semantics of the header widget for expanded panel.
+    final Finder collapsedHeader = find.byKey(collapsedKey);
+    expect(tester.getSemantics(collapsedHeader), matchesSemantics(
+      label: 'Collapsed',
+    ));
+
+    handle.dispose();
+  });
+
   testWidgets('Panel header has semantics, canTapOnHeader = true', (WidgetTester tester) async {
     const Key expandedKey = Key('expanded');
     const Key collapsedKey = Key('collapsed');