Question

我想知道如何在flutter小部件测试中完成未完成的情况时进行测试。

只要未来未解决，小部件就应显示微调框。

我整理了这个测试用例：

testWidgets(
  'should show a spinner when loading',
  (WidgetTester tester) async {
    when(valueRepository.getValues())
        .thenAnswer((_) => Future.delayed(Duration(seconds: 30), () => []));
    await tester.pumpWidget(withApp(ValueListPage(
      valueRepository: valueRepository,
    )));

    await tester.pumpAndSettle(
        Duration(seconds: 10), EnginePhase.build, Duration(minutes: 1));

    expect(find.byType(CircularProgressIndicator), findsOneWidget);
  },
);

结果：未来得到解决，期望失败。

注意：withApp使用本地化初始化一个App。因此，我必须致电tester.pumpAndSettle()等待l10n。

Answer 1

尝试

testWidgets(
  'should show a spinner when loading',
  (WidgetTester tester) async {
    tester.runAsync(() async {
      when(valueRepository.getValues())
          .thenAnswer((_) => Future.delayed(Duration(seconds: 30), () => []));
      await tester.pumpWidget(withApp(ValueListPage(
        valueRepository: valueRepository,
      )));

      await tester.pumpAndSettle(
          Duration(seconds: 10), EnginePhase.build, Duration(minutes: 1));

      expect(find.byType(CircularProgressIndicator), findsOneWidget);
    });
  },
);

默认情况下，测试是使用fakeAsync运行的，并且某些异步代码无法使用fakeAsync正常运行。

Answer 2

我找到了一个使用fakeAsync的可行解决方案：

testWidgets(
  'should show a spinner when loading',
  (WidgetTester tester) async {
      when(valueRepository.getValues()).thenAnswer(
          (_) => Future.delayed(Duration(seconds: 1), () => []));
      await tester.pumpWidget(withApp(ValueListPage(
        valueRepository: valueRepository,
      )));

      await tester.pump();

      expect(find.byType(CircularProgressIndicator), findsOneWidget);
      await tester.pumpAndSettle();
      expect(find.byType(CircularProgressIndicator), findsNothing);
  },
);

Answer 3

尝试使用完成程序在等待时保留AsyncSnapshot。例如：

testWidgets('should show a spinner when loading',(WidgetTester tester) async {

    Completer completer = Completer();
    when(valueRepository.getValues())
       .thenAnswer((_) => completer.future);
    await tester.pumpWidget(withApp(ValueListPage(
    valueRepository: valueRepository,
    )));

    expect(find.byType(CircularProgressIndicator), findsOneWidget); 
 },
);

如何使用未解决的Future进行部件测试FutureBuilder

3 个答案: