packages/flutter/test/widgets/app_test.dart

// Copyright 2018 The Chromium 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/material.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';

void main() {
  testWidgets('WidgetsApp with builder only', (WidgetTester tester) async {
    final GlobalKey key = GlobalKey();
    await tester.pumpWidget(
      WidgetsApp(
        key: key,
        builder: (BuildContext context, Widget child) {
          return const Placeholder();
        },
        color: const Color(0xFF123456),
      ),
    );
    expect(find.byKey(key), findsOneWidget);
  });

  group('error control test', () {
    Future<void> expectFlutterError({
      GlobalKey<NavigatorState> key,
      Widget widget,
      WidgetTester tester,
      String errorMessage,
    }) async {
      await tester.pumpWidget(widget);
      FlutterError error;
      try {
        key.currentState.pushNamed('/path');
      } on FlutterError catch (e) {
        error = e;
      } finally {
        expect(error, isNotNull);
        expect(error, isFlutterError);
        expect(error.toStringDeep(), errorMessage);
      }
    }

    testWidgets('push unknown route when onUnknownRoute is null', (WidgetTester tester) async {
      final GlobalKey<NavigatorState> key = GlobalKey<NavigatorState>();
      expectFlutterError(
        key: key,
        tester: tester,
        widget: MaterialApp(
          navigatorKey: key,
          home: Container(),
          onGenerateRoute: (_) => null,
        ),
        errorMessage:
          'FlutterError\n'
          '   Could not find a generator for route RouteSettings("/path", null)\n'
          '   in the _WidgetsAppState.\n'
          '   Generators for routes are searched for in the following order:\n'
          '    1. For the "/" route, the "home" property, if non-null, is used.\n'
          '    2. Otherwise, the "routes" table is used, if it has an entry for\n'
          '   the route.\n'
          '    3. Otherwise, onGenerateRoute is called. It should return a\n'
          '   non-null value for any valid route not handled by "home" and\n'
          '   "routes".\n'
          '    4. Finally if all else fails onUnknownRoute is called.\n'
          '   Unfortunately, onUnknownRoute was not set.\n',
      );
    });

    testWidgets('push unknown route when onUnknownRoute returns null', (WidgetTester tester) async {
      final GlobalKey<NavigatorState> key = GlobalKey<NavigatorState>();
      expectFlutterError(
        key: key,
        tester: tester,
        widget: MaterialApp(
          navigatorKey: key,
          home: Container(),
          onGenerateRoute: (_) => null,
          onUnknownRoute: (_) => null,
        ),
        errorMessage:
          'FlutterError\n'
          '   The onUnknownRoute callback returned null.\n'
          '   When the _WidgetsAppState requested the route\n'
          '   RouteSettings("/path", null) from its onUnknownRoute callback,\n'
          '   the callback returned null. Such callbacks must never return\n'
          '   null.\n' ,
      );
    });
  });
}