Adds cupertino picker semantics test (#161768)

Adds a test

## Pre-launch Checklist

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there for submitting PRs.
- [ ] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [ ] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [ ] I signed the [CLA].
- [ ] I listed at least one issue that this PR fixes in the description
above.
- [ ] I updated/added relevant documentation (doc comments with `///`).
- [ ] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [ ] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [ ] All existing and new tests are passing.

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[Data Driven Fixes]:
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packages/flutter/test/cupertino/picker_test.dart

@@ -10,6 +10,7 @@ import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import '../rendering/rendering_tester.dart';
+import '../widgets/semantics_tester.dart';
 
 class SpyFixedExtentScrollController extends FixedExtentScrollController {
   /// Override for test visibility only.
@@ -54,6 +55,51 @@ void main() {
     );
   });
 
+  testWidgets('Picker semantics', (WidgetTester tester) async {
+    final SemanticsTester semantics = SemanticsTester(tester);
+
+    await tester.pumpWidget(
+      CupertinoApp(
+        home: SizedBox(
+          height: 300.0,
+          width: 300.0,
+          child: CupertinoPicker(
+            itemExtent: 50.0,
+            onSelectedItemChanged: (_) {},
+            children: List<Widget>.generate(13, (int index) {
+              return SizedBox(height: 50.0, width: 300.0, child: Text(index.toString()));
+            }),
+          ),
+        ),
+      ),
+    );
+    expect(
+      semantics,
+      includesNodeWith(
+        value: '0',
+        increasedValue: '1',
+        actions: <SemanticsAction>[SemanticsAction.increase],
+      ),
+    );
+
+    final FixedExtentScrollController hourListController =
+        tester.widget<ListWheelScrollView>(find.byType(ListWheelScrollView)).controller!
+            as FixedExtentScrollController;
+
+    hourListController.jumpToItem(11);
+    await tester.pumpAndSettle();
+    expect(
+      semantics,
+      includesNodeWith(
+        value: '11',
+        increasedValue: '12',
+        decreasedValue: '10',
+        actions: <SemanticsAction>[SemanticsAction.increase, SemanticsAction.decrease],
+      ),
+    );
+    semantics.dispose();
+  });
+
   group('layout', () {
     // Regression test for https://github.com/flutter/flutter/issues/22999
     testWidgets('CupertinoPicker.builder test', (WidgetTester tester) async {

packages/flutter/test/widgets/semantics_tester.dart

@@ -560,6 +560,8 @@ class SemanticsTester {
     String? label,
     String? value,
     String? hint,
+    String? increasedValue,
+    String? decreasedValue,
     TextDirection? textDirection,
     List<SemanticsAction>? actions,
     List<SemanticsFlag>? flags,
@@ -597,6 +599,12 @@ class SemanticsTester {
       if (hint != null && node.hint != hint) {
         return false;
       }
+      if (increasedValue != null && node.increasedValue != increasedValue) {
+        return false;
+      }
+      if (decreasedValue != null && node.decreasedValue != decreasedValue) {
+        return false;
+      }
       if (attributedHint != null &&
           (attributedHint.string != node.attributedHint.string ||
               !_stringAttributesEqual(attributedHint.attributes, node.attributedHint.attributes))) {
@@ -916,6 +924,8 @@ class _IncludesNodeWith extends Matcher {
     this.label,
     this.value,
     this.hint,
+    this.increasedValue,
+    this.decreasedValue,
     this.textDirection,
     this.actions,
     this.flags,
@@ -931,6 +941,8 @@ class _IncludesNodeWith extends Matcher {
              actions != null ||
              flags != null ||
              tags != null ||
+             increasedValue != null ||
+             decreasedValue != null ||
              scrollPosition != null ||
              scrollExtentMax != null ||
              scrollExtentMin != null ||
@@ -943,6 +955,8 @@ class _IncludesNodeWith extends Matcher {
   final String? label;
   final String? value;
   final String? hint;
+  final String? increasedValue;
+  final String? decreasedValue;
   final TextDirection? textDirection;
   final List<SemanticsAction>? actions;
   final List<SemanticsFlag>? flags;
@@ -963,6 +977,8 @@ class _IncludesNodeWith extends Matcher {
           label: label,
           value: value,
           hint: hint,
+          increasedValue: increasedValue,
+          decreasedValue: decreasedValue,
           textDirection: textDirection,
           actions: actions,
           flags: flags,
@@ -1000,6 +1016,8 @@ class _IncludesNodeWith extends Matcher {
       if (actions != null) 'actions "${actions!.join(', ')}"',
       if (flags != null) 'flags "${flags!.join(', ')}"',
       if (tags != null) 'tags "${tags!.join(', ')}"',
+      if (increasedValue != null) 'increasedValue "$increasedValue"',
+      if (decreasedValue != null) 'decreasedValue "$decreasedValue"',
       if (scrollPosition != null) 'scrollPosition "$scrollPosition"',
       if (scrollExtentMax != null) 'scrollExtentMax "$scrollExtentMax"',
       if (scrollExtentMin != null) 'scrollExtentMin "$scrollExtentMin"',
@@ -1021,6 +1039,8 @@ Matcher includesNodeWith({
   AttributedString? attributedValue,
   String? hint,
   AttributedString? attributedHint,
+  String? increasedValue,
+  String? decreasedValue,
   TextDirection? textDirection,
   List<SemanticsAction>? actions,
   List<SemanticsFlag>? flags,
@@ -1039,6 +1059,8 @@ Matcher includesNodeWith({
     hint: hint,
     attributedHint: attributedHint,
     textDirection: textDirection,
+    increasedValue: increasedValue,
+    decreasedValue: decreasedValue,
     actions: actions,
     flags: flags,
     tags: tags,