flutter riverpod：如何测试 asyncvalue.error？

Question

当我的 Riverpod FutureProvider 返回 AsyncValue.error 时，我无法测试它。

我尝试了如下所示的测试：

// Future provider  
final ipsProvider = FutureProvider.autoDispose((_) =>  IpRepository().fetchIps());

// Widget to be tested
class ExampleWidget extends ConsumerWidget {
  @override
  Widget build(BuildContext context, ScopedReader watch) {
    // hooks
    AsyncValue<List<Ip>> ips = watch(ipsProvider);
    return Container(
      child: ips.when(
        data: (data) => randomWidget,
        loading: () => progressIndicator,
        error: (_, stack) => Text('YesMan'),
      ),
    );
  }
}

// Test: I am trying to find a Text widget containing message 'YesMan'
testWidgets('ExampleWidget | error', (WidgetTester tester) async 
  await tester.pumpWidget(
        ProviderScope(
            overrides: [
              ipsProvider.overrideWithValue(AsyncValue.error('randomErrorMessage')),
            ],
            child: MaterialApp(
              home: Builder(builder: (context) {
                return ExampleWidget();
              }),
            ),
          ),
      );
      final finderError = find.text('YesMan');
      expect(finderError, findsOneWidget);
    });

我希望测试返回带有消息“randomError”的文本小部件，但它会引发如下异常：

══╡ EXCEPTION CAUGHT BY FLUTTER TEST FRAMEWORK The following message was thrown running a test: randomErrorMessage When the exception was thrown, this was the stack:

知道如何在 Riverpod 中测试 AsyncValue.error 案例吗？

谢谢

Answer 1

而不是 overrideWithValue 尝试 overrideProvider 并运行 future.error 以便 FutureProvider 捕获它

class ExampleWidget extends ConsumerWidget {
  @override
  Widget build(BuildContext context, ScopedReader watch) {
    // hooks
    AsyncValue<String> ips = watch(ipsProvider);
    return Container(
      child: ips.when(
        data: (data) => SizedBox(),
        loading: () => CircularProgressIndicator(),
        error: (_, stack) => Text('YesMan'),
      ),
    );
  }
}

testWidgets('ExampleWidget | error', (WidgetTester tester) async {
    await tester.pumpWidget(
      ProviderScope(
        overrides: [
          ipsProvider.overrideWithProvider(FutureProvider((_) => Future.error('error'))),
        ],
        child: MaterialApp(
          home: Builder(builder: (context) {
            return ExampleWidget();
          }),
        ),
      ),
    );

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

    await tester.pump();

    final finderError = find.text('YesMan');
    expect(finderError, findsOneWidget);
  });