Flutter Widget测试与NetworkImage [英] Flutter Widget Tests with NetworkImage

问题描述

我有一个窗口小部件和 NetworkImage （到目前为止带有硬编码的网址）。

我想对这个窗口小部件进行测试，但是运行窗口小部件测试时得到了404（URL为100％有效）。

如何制作 NetworkImages 加载自身还是（更好）忽略它们，这样我的测试就不会因为404而失败？

I have a Widget with NetworkImage (so far with hard-coded url).
I would like to widget test this Widget, but I got 404 when I run widget test (url is 100% valid).
How can I make NetworkImages load themselves or (which would be better) ignore them so that my tests won't fail because of 404?

推荐答案

在小部件测试中，默认的HTTP客户端已替换，该参数始终返回400s。在 flutter_markdown repo 以及其他几个地方。我曾经将其复制并粘贴到每个项目中，但是我做了足够多次，以至于变得很无聊。

In widget tests, the default HTTP client has been replaced with one that always returns 400s. There's a sample on how to do this in the flutter_markdown repo along with couple other places. I used to copy and paste this to every project, but I did it enough times to get quite bored.

（我）现在有一个用于此的库，称为< a href = https://github.com/roughike/image_test_utils rel = noreferrer> image_test_utils 。您可以使用 provideMockedNetworkImages 方法包装小部件测试，该方法将模拟的HTTP客户端替换为始终返回透明图像的HTTP客户端。

There's now a library for this (by me), called "image_test_utils". You can wrap your widget tests with a provideMockedNetworkImages method, which replaces the mocked HTTP client with one that always returns transparent images. Which in turn makes your tests pass.

pubspec.yaml：

dev_dependencies:
  image_test_utils: ^1.0.0

my_image_test.dart：

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:image_test_utils/image_test_utils.dart';

void main() {
  testWidgets('my image test', (WidgetTester tester) async {
    provideMockedNetworkImages(() async {
      /// Now we can pump NetworkImages without crashing our tests. Yay!
      await tester.pumpWidget(
        MaterialApp(
          home: Image.network('https://example.com/image.png'),
        ),
      );

      /// No crashes.
    });
  });
}

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