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如何编写一个Flutter方法的单元测试,该方法将在稍后完成并具有未来?

flutter-test

0

Jonathan · 技术社区 · 5 年前

这是我的测试:

    test('mark as viewed', () {
      final a = Asset();
      expect(a.viewed, false);
      a.markAsViewed();
      expect(a.viewed, true);
    });

下面是它正在测试的方法:

  void markAsViewed() {
    viewed = true;
    Repository.get().saveToStorage();
  }

这个 saveToStorage() 方法是一个异步,我只需要在后台执行它。

Make sure to use [expectAsync] or the [completes] matcher when testing async code. 但我不知道怎么做。有人能给我解释一下或者给我指一下正确的文件吗?我找不到任何关于如何处理这些异步的东西 Future 那是要退回的,但要单独完成。

明确地说-这个单元测试不是测试它是否被保存到存储中,只是一个关于设置的基本测试 viewed true .

编辑

package:flutter/src/services/platform_channel.dart 319:7  MethodChannel.invokeMethod
===== asynchronous gap ===========================
dart:async                                                _asyncErrorWrapperHelper
package:exec_pointers/asset_details.dart                  Repository.saveToStorage
package:exec_pointers/asset_details.dart 64:22            Asset.markAsViewed
test/asset_details_test.dart 57:9                         main.<fn>.<fn>
This test failed after it had already completed. Make sure to use [expectAsync]
or the [completes] matcher when testing async code.

0 回复 | 直到 5 年前

1

0

Nkosi 5 年前

此代码与实现问题紧密耦合,这些问题使隔离测试变得困难。

例如

class Asset {
    Asset({Repository repository}) {
        this.repository = repository;
    }

    final Repository repository;
    bool viewed;

    void markAsViewed() {
        viewed = true;
        repository.saveToStorage();
    }

    //...
}

// Create a Mock Repository using the Mock class provided by the Mockito package.
// Create new instances of this class in each test.
class MockRepository extends Mock implements Repository {}

main() {
  test('mark as viewed', () {
    final repo = MockRepository();
    // Use Mockito to do nothing when it calls the repository
    when(repo.saveToStorage())
      .thenAnswer((_) async => { });

    final subject = Asset(repo);
    expect(subject.viewed, false);
    subject.markAsViewed();
    expect(subject.viewed, true);
    //
    verify(repo.saveToStorage());
  });
}

现在应该可以在不出现依赖项的意外行为的情况下执行测试。

参考 An introduction to unit testing
Mock dependencies using Mockito
参考 mockito 4.1.1