flutter_flutter/packages/flutter/test/material/debug_test.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';

void main() {
  testWidgets('debugCheckHasMaterial control test', (WidgetTester tester) async {
    await tester.pumpWidget(const Center(child: Chip(label: Text('label'))));
    final dynamic exception = tester.takeException();
    expect(exception, isFlutterError);
    final error = exception as FlutterError;
    expect(error.diagnostics.length, 5);
    expect(error.diagnostics[2].level, DiagnosticLevel.hint);
    expect(
      error.diagnostics[2].toStringDeep(),
      equalsIgnoringHashCodes(
        'To introduce a Material widget, you can either directly include\n'
        'one, or use a widget that contains Material itself, such as a\n'
        'Card, Dialog, Drawer, or Scaffold.\n',
      ),
    );
    expect(error.diagnostics[3], isA<DiagnosticsProperty<Element>>());
    expect(error.diagnostics[4], isA<DiagnosticsBlock>());
    expect(
      error.toStringDeep(),
      startsWith(
        'FlutterError\n'
        '   No Material widget found.\n'
        '   Chip widgets require a Material widget ancestor within the\n'
        '   closest LookupBoundary.\n'
        '   In Material Design, most widgets are conceptually "printed" on a\n'
        "   sheet of material. In Flutter's material library, that material\n"
        '   is represented by the Material widget. It is the Material widget\n'
        '   that renders ink splashes, for instance. Because of this, many\n'
        '   material library widgets require that there be a Material widget\n'
        '   in the tree above them.\n'
        '   To introduce a Material widget, you can either directly include\n'
        '   one, or use a widget that contains Material itself, such as a\n'
        '   Card, Dialog, Drawer, or Scaffold.\n'
        '   The specific widget that could not find a Material ancestor was:\n'
        '     Chip\n'
        '   The ancestors of this widget were:\n'
        '     Center\n',
        // End of ancestor chain omitted, not relevant for test.
      ),
    );
  });

  testWidgets('debugCheckHasMaterialLocalizations control test', (WidgetTester tester) async {
    await tester.pumpWidget(const Center(child: BackButton()));
    final dynamic exception = tester.takeException();
    expect(exception, isFlutterError);
    final error = exception as FlutterError;
    expect(error.diagnostics.length, 6);
    expect(error.diagnostics[3].level, DiagnosticLevel.hint);
    expect(
      error.diagnostics[3].toStringDeep(),
      equalsIgnoringHashCodes(
        'To introduce a MaterialLocalizations, either use a MaterialApp at\n'
        'the root of your application to include them automatically, or\n'
        'add a Localization widget with a MaterialLocalizations delegate.\n',
      ),
    );
    expect(error.diagnostics[4], isA<DiagnosticsProperty<Element>>());
    expect(error.diagnostics[5], isA<DiagnosticsBlock>());
    expect(
      error.toStringDeep(),
      startsWith(
        'FlutterError\n'
        '   No MaterialLocalizations found.\n'
        '   BackButton widgets require MaterialLocalizations to be provided\n'
        '   by a Localizations widget ancestor.\n'
        '   The material library uses Localizations to generate messages,\n'
        '   labels, and abbreviations.\n'
        '   To introduce a MaterialLocalizations, either use a MaterialApp at\n'
        '   the root of your application to include them automatically, or\n'
        '   add a Localization widget with a MaterialLocalizations delegate.\n'
        '   The specific widget that could not find a MaterialLocalizations\n'
        '   ancestor was:\n'
        '     BackButton\n'
        '   The ancestors of this widget were:\n'
        '     Center\n',
        // End of ancestor chain omitted, not relevant for test.
      ),
    );
  });

  testWidgets('debugCheckHasScaffold control test', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData(
          pageTransitionsTheme: const PageTransitionsTheme(
            builders: <TargetPlatform, PageTransitionsBuilder>{
              TargetPlatform.android: FadeUpwardsPageTransitionsBuilder(),
            },
          ),
        ),
        home: Builder(
          builder: (BuildContext context) {
            showBottomSheet(context: context, builder: (BuildContext context) => Container());
            return Container();
          },
        ),
      ),
    );
    final dynamic exception = tester.takeException();
    expect(exception, isFlutterError);
    final error = exception as FlutterError;
    expect(error.diagnostics.length, 5);
    expect(error.diagnostics[2], isA<DiagnosticsProperty<Element>>());
    expect(error.diagnostics[3], isA<DiagnosticsBlock>());
    expect(error.diagnostics[4].level, DiagnosticLevel.hint);
    expect(
      error.diagnostics[4].toStringDeep(),
      equalsIgnoringHashCodes(
        'Typically, the Scaffold widget is introduced by the MaterialApp\n'
        'or WidgetsApp widget at the top of your application widget tree.\n',
      ),
    );
    expect(
      error.toStringDeep(),
      startsWith(
        'FlutterError\n'
        '   No Scaffold widget found.\n'
        '   Builder widgets require a Scaffold widget ancestor.\n'
        '   The specific widget that could not find a Scaffold ancestor was:\n'
        '     Builder\n'
        '   The ancestors of this widget were:\n'
        '     Semantics\n'
        '     Builder\n',
      ),
    );
    expect(
      error.toStringDeep(),
      endsWith(
        '     [root]\n'
        '   Typically, the Scaffold widget is introduced by the MaterialApp\n'
        '   or WidgetsApp widget at the top of your application widget tree.\n',
      ),
    );
  });

  testWidgets('debugCheckHasScaffoldMessenger control test', (WidgetTester tester) async {
    final scaffoldKey = GlobalKey<ScaffoldState>();
    final scaffoldMessengerKey = GlobalKey<ScaffoldMessengerState>();
    final snackBar = SnackBar(
      content: const Text('Snack'),
      action: SnackBarAction(label: 'Test', onPressed: () {}),
    );
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: ScaffoldMessenger(
          key: scaffoldMessengerKey,
          child: Builder(
            builder: (BuildContext context) {
              return Scaffold(key: scaffoldKey, body: Container());
            },
          ),
        ),
      ),
    );
    final exceptions = <dynamic>[];
    final FlutterExceptionHandler? oldHandler = FlutterError.onError;
    FlutterError.onError = (FlutterErrorDetails details) {
      exceptions.add(details.exception);
    };
    // ScaffoldMessenger shows SnackBar.
    scaffoldMessengerKey.currentState!.showSnackBar(snackBar);
    await tester.pumpAndSettle();

    // Pump widget to rebuild without ScaffoldMessenger
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: Scaffold(key: scaffoldKey, body: Container()),
      ),
    );
    // Tap SnackBarAction to dismiss.
    // The SnackBarAction should assert we still have an ancestor
    // ScaffoldMessenger in order to dismiss the SnackBar from the
    // Scaffold.
    await tester.tap(find.text('Test'));
    FlutterError.onError = oldHandler;

    expect(exceptions.length, 1);
    expect(exceptions.single.runtimeType, FlutterError);
    final error = exceptions.first as FlutterError;
    expect(error.diagnostics.length, 5);
    expect(error.diagnostics[2], isA<DiagnosticsProperty<Element>>());
    expect(error.diagnostics[3], isA<DiagnosticsBlock>());
    expect(error.diagnostics[4].level, DiagnosticLevel.hint);
    expect(
      error.diagnostics[4].toStringDeep(),
      equalsIgnoringHashCodes(
        'Typically, the ScaffoldMessenger widget is introduced by the\n'
        'MaterialApp at the top of your application widget tree.\n',
      ),
    );
    expect(
      error.toStringDeep(),
      startsWith(
        'FlutterError\n'
        '   No ScaffoldMessenger widget found.\n'
        '   SnackBarAction widgets require a ScaffoldMessenger widget\n'
        '   ancestor.\n'
        '   The specific widget that could not find a ScaffoldMessenger\n'
        '   ancestor was:\n'
        '     SnackBarAction\n'
        '   The ancestors of this widget were:\n'
        '     TextButtonTheme\n'
        '     Padding\n'
        '     Row\n',
      ),
    );
    expect(
      error.toStringDeep(),
      endsWith(
        '     [root]\n'
        '   Typically, the ScaffoldMessenger widget is introduced by the\n'
        '   MaterialApp at the top of your application widget tree.\n',
      ),
    );
  });
}