rename local functions with `_`s (#102991)

packages/flutter/test/cupertino/date_picker_test.dart

@@ -1518,7 +1518,7 @@ void main() {
   });
 
   testWidgets('DatePicker adapts to MaterialApp dark mode', (WidgetTester tester) async {
-    Widget _buildDatePicker(Brightness brightness) {
+    Widget buildDatePicker(Brightness brightness) {
       return MaterialApp(
         theme: ThemeData(brightness: brightness),
         home: CupertinoDatePicker(
@@ -1530,14 +1530,14 @@ void main() {
     }
 
     // CupertinoDatePicker with light theme.
-    await tester.pumpWidget(_buildDatePicker(Brightness.light));
+    await tester.pumpWidget(buildDatePicker(Brightness.light));
     RenderParagraph paragraph = tester.renderObject(find.text('October').first);
     expect(paragraph.text.style!.color, CupertinoColors.label);
     // Text style should not return unresolved color.
     expect(paragraph.text.style!.color.toString().contains('UNRESOLVED'), isFalse);
 
     // CupertinoDatePicker with dark theme.
-    await tester.pumpWidget(_buildDatePicker(Brightness.dark));
+    await tester.pumpWidget(buildDatePicker(Brightness.dark));
     paragraph = tester.renderObject(find.text('October').first);
     expect(paragraph.text.style!.color, CupertinoColors.label);
     // Text style should not return unresolved color.
@@ -1545,7 +1545,7 @@ void main() {
   });
 
   testWidgets('TimerPicker adapts to MaterialApp dark mode', (WidgetTester tester) async {
-    Widget _buildTimerPicker(Brightness brightness) {
+    Widget buildTimerPicker(Brightness brightness) {
       return MaterialApp(
         theme: ThemeData(brightness: brightness),
         home: CupertinoTimerPicker(
@@ -1557,14 +1557,14 @@ void main() {
     }
 
     // CupertinoTimerPicker with light theme.
-    await tester.pumpWidget(_buildTimerPicker(Brightness.light));
+    await tester.pumpWidget(buildTimerPicker(Brightness.light));
     RenderParagraph paragraph = tester.renderObject(find.text('hours'));
     expect(paragraph.text.style!.color, CupertinoColors.label);
     // Text style should not return unresolved color.
     expect(paragraph.text.style!.color.toString().contains('UNRESOLVED'), isFalse);
 
     // CupertinoTimerPicker with light theme.
-    await tester.pumpWidget(_buildTimerPicker(Brightness.dark));
+    await tester.pumpWidget(buildTimerPicker(Brightness.dark));
     paragraph = tester.renderObject(find.text('hours'));
     expect(paragraph.text.style!.color, CupertinoColors.label);
     // Text style should not return unresolved color.

packages/flutter/test/cupertino/form_row_test.dart

@@ -170,7 +170,7 @@ void main() {
     const Widget prefix = Text('Prefix');
     const Widget helper = Text('Helper');
 
-    Widget _buildFormRow(Brightness brightness) {
+    Widget buildFormRow(Brightness brightness) {
       return MaterialApp(
         theme: ThemeData(brightness: brightness),
         home: const Center(
@@ -184,7 +184,7 @@ void main() {
     }
 
     // CupertinoFormRow with light theme.
-    await tester.pumpWidget(_buildFormRow(Brightness.light));
+    await tester.pumpWidget(buildFormRow(Brightness.light));
     RenderParagraph helperParagraph = tester.renderObject(find.text('Helper'));
     expect(helperParagraph.text.style!.color, CupertinoColors.label);
     // Text style should not return unresolved color.
@@ -195,7 +195,7 @@ void main() {
     expect(prefixParagraph.text.style!.color.toString().contains('UNRESOLVED'), isFalse);
 
     // CupertinoFormRow with light theme.
-    await tester.pumpWidget(_buildFormRow(Brightness.dark));
+    await tester.pumpWidget(buildFormRow(Brightness.dark));
     helperParagraph = tester.renderObject(find.text('Helper'));
     expect(helperParagraph.text.style!.color, CupertinoColors.label);
     // Text style should not return unresolved color.

packages/flutter/test/cupertino/picker_test.dart

@@ -425,7 +425,7 @@ void main() {
   });
 
   testWidgets('Picker adapts to MaterialApp dark mode', (WidgetTester tester) async {
-    Widget _buildCupertinoPicker(Brightness brightness) {
+    Widget buildCupertinoPicker(Brightness brightness) {
       return MaterialApp(
         theme: ThemeData(brightness: brightness),
         home: Align(
@@ -450,14 +450,14 @@ void main() {
     }
 
     // CupertinoPicker with light theme.
-    await tester.pumpWidget(_buildCupertinoPicker(Brightness.light));
+    await tester.pumpWidget(buildCupertinoPicker(Brightness.light));
     RenderParagraph paragraph = tester.renderObject(find.text('1'));
     expect(paragraph.text.style!.color, CupertinoColors.label);
     // Text style should not return unresolved color.
     expect(paragraph.text.style!.color.toString().contains('UNRESOLVED'), isFalse);
 
     // CupertinoPicker with dark theme.
-    await tester.pumpWidget(_buildCupertinoPicker(Brightness.dark));
+    await tester.pumpWidget(buildCupertinoPicker(Brightness.dark));
     paragraph = tester.renderObject(find.text('1'));
     expect(paragraph.text.style!.color, CupertinoColors.label);
     // Text style should not return unresolved color.