flutterでローカライズ系のテスト

import 'dart:ui';
import 'package:app_name/generated/l10n.dart';
import 'package:app_name/utils/utils.dart';
import 'package:flutter/material.dart';
import 'package:flutter_localizations/flutter_localizations.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:intl/date_symbol_data_local.dart';

// ローカライズ系のテストのため
Widget buildFrame({
  Locale locale,
  Iterable<LocalizationsDelegate<dynamic>> delegates,
  WidgetBuilder buildContent,
  LocaleResolutionCallback localeResolutionCallback,
}) {
  return WidgetsApp(
    color: Colors.white,
    locale: locale,
    localizationsDelegates: const <LocalizationsDelegate<dynamic>>[
      GlobalMaterialLocalizations.delegate,
      GlobalWidgetsLocalizations.delegate,
      GlobalCupertinoLocalizations.delegate,
      S.delegate,
    ],
    localeResolutionCallback: localeResolutionCallback,
    supportedLocales: S.delegate.supportedLocales,
    onGenerateRoute: (settings) {
      return PageRouteBuilder<void>(pageBuilder: (context, _, __) {
        return buildContent(context);
      });
    },
  );
}

void main() {
  testWidgets('Localizations.localeFor in a WidgetsApp with system locale',
      (tester) async {
    BuildContext pageContext;
    await tester.pumpWidget(buildFrame(buildContent: (context) {
      pageContext = context;

      return Column(
        children: [
          Text(
            DateUtil.fromTimeFormat(
              pageContext,
              DateTime(2021, 4, 12, 11, 00),
            ),
          ),
          Text(
            DateUtil.dateWithDayFormat(
              pageContext,
              DateTime(2021, 4, 12, 11, 00),
            ),
          ),
        ],
      );
    }));

    await tester.idle();
    // The async delegator load will require build on the next frame. Thus, pump
    await tester.pump();

    debugPrint('fromTimeFormatをテスト');
    expect(find.text('4/12(月) 11:00~'), findsOneWidget);

    debugPrint('dateWithDayFormatをテスト');
    expect(find.text('4/12 (月)'), findsOneWidget);
  });