我跟踪this example是为了测试101是否出现在我的视图中，但即使Flutter 构建树显示小部件存在，我仍然得到以下异常:

══╡ EXCEPTION CAUGHT BY FLUTTER TEST FRAMEWORK ╞════════════════════════════════════════════════════
The following TestFailure was thrown running a test:
Expected: exactly one matching node in the widget tree
  Actual: _WidgetFinder:<zero widgets with the given widget
(CircularProgressIndicator(<indeterminate>)) (ignoring offstage widgets)>
   Which: means none were found but one was expected

When the exception was thrown, this was the stack:
#4      main.<anonymous closure> (file:///D:/xxxx/xxxx/xxxx/test/widget_test/widget_test.dart:173:5)
<asynchronous suspension>
<asynchronous suspension>
(elided one frame from package:stack_trace)

This was caught by the test expectation on the following line:
  file:///D:/xxxx/xxxx/xxxx/test/widget_test/widget_test.dart line 173
The test description was:
  ViewRequest: Waiting Types List
════════════════════════════════════════════════════════════════════════════════════════════════════

Edit

我做了一个方法，只用一个101小部件作为它的"子部件"来构建100:

Widget createMockViewRequest() {
  return MaterialApp(
      title: 'SmartDevice Simulator',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const CircularProgressIndicator());
}

以下测试仍然失败，但有一个例外:

testWidgets('ViewRequest: Waiting Types List', (WidgetTester tester) async {
  const childWidget = CircularProgressIndicator();

  // Build our app and trigger a frame.
  await tester.pumpWidget(createMockViewRequest());

  // Verify that the page is loading until we receive the types.
  expect(find.byWidget(childWidget), findsOneWidget);

  await tester.pumpAndSettle();
});

我做错什么了吗？也许100不算集装箱？但在这种情况下，我不明白为什么不应该这样做.