Flutter小部件测试：无法使用find.byWidget()找到小部件

b4wnujal 于 2022-11-25 发布在 Flutter

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我按照此示例测试视图中是否存在**CircularProgressIndicator**，但即使Flutter构建树显示存在该小部件，我仍不断收到以下异常：

══╡ 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
════════════════════════════════════════════════════════════════════════════════════════════════════

编辑

我创建了一个方法，它只使用一个**CircularProgressIndicatorWidget作为MaterialApp的“子对象”来构建MaterialApp**：

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

以下测试仍然失败，并出现相同的异常：

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();
});

我做错了什么吗？也许**MaterialApp**不算容器？但在这种情况下，我不明白为什么它不应该。

flutter

来源：https://stackoverflow.com/questions/74523912/flutter-widget-test-cannot-find-widget-using-find-bywidget

2条答案

按热度按时间

wa7juj8i1#

为了使它工作，有一些事情要改变。
首先，如果您在测试具有无限动画（如CircularProgressIndicator）的小部件时使用await tester.pumpAndSettle()，测试将失败，因为它正在等待最后一帧更新，但动画从未结束，因此引发超时。
除此之外，您的测试之所以失败是因为您使用的是finder，您试图在UI中找到提供给expect的完全相同的示例，但事实并非如此，因为在UI中构建的示例与您在测试中创建的示例不同，在本例中，如果您想检查UI上是否有CircularProgressIndicator，您应该使用find.byType查找器，它在已构建的小部件中搜索所提供类型的小部件。

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63lcw9qa2#

你必须像这样改变你的例子：

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

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

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

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

或类似于：

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

  testWidgets('ViewRequest: Waiting Types List', (WidgetTester tester) async {
    // Build our app and trigger a frame.
    await tester.pumpWidget(createMockViewRequest());

    // Verify that the page is loading until we receive the types.
    expect(find.byType(CircularProgressIndicator), findsOneWidget);
  });

请注意，我删除了await tester.pumpAndSettle();，因为它会在页面上的动画完成时等待，但CircularProgressIndicator将旋转到无穷大，因此您将遇到超时异常。

赞(0）回复(0）举报 2022-11-25

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Flutter小部件测试：无法使用find.byWidget()找到小部件

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2条答案

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