database - Aqueduct :状态不佳:未找到 '_MyEntity' 的实体。您是否忘记创建一个 'ManagedContext' ？

Question

我正在开始一个新项目并希望使用测试驱动开发。这是我的实体:

import 'package:aqueduct/aqueduct.dart';

class MyEntity extends ManagedObject<_MyEntity> implements _MyEntity {}class _MyEntity {
  @primaryKey
  int id;
  int myValue;
}

当我从文本文件中提取一些数据时，我想独立于数据库使用 MyEntity。但是当我尝试像这样测试它时

void main() {
  test('DatabaseBuilder returns multiple entities', () {
    List<MyEntity> entities = [];
    entities.add(MyEntity());
    expect(entities.length, greaterThan(0));
  });
}

我收到以下错误:

Bad state: No entity found for '_MyEntity. Did you forget to create a 'ManagedContext'?

我不允许将实体用于非数据库逻辑吗？

Answer 1

This question已在 Aqueduct Slack channel 上得到答复所以我把它移到这里更容易搜索。

Reductions answered :

You will need to start a TestHarness with TestHarnessORMMixin mixed in. After that you can used the MnagedObject (sic) however you find fit.

joeconwaystk followed up :

Yes, what Reductions said… the framework handles TDD with the ORM by creating a temporary schema in your database server during testing (with the TestHarnessORMixin)

所以我更新了 test/harness/app.dart 文件，看起来像这样:

class Harness extends TestHarness<MyChannel> with TestHarnessORMMixin {
  @override
  Future onSetUp() async {
    await resetData();
  }

  @override
  Future onTearDown() async {}

  @override
  ManagedContext get context => channel.context;
}

我的测试看起来像这样:

Future main() async {
  final harness = Harness()..install();

  test('DatabaseBuilder returns multiple entities', () {
    List<MyEntity> entities = [];
    entities.add(MyEntity());
    expect(entities.length, greaterThan(0));
  });
}

即使我没有直接使用线束，安装它也足以消除错误。

如果您不喜欢该方法，我发现的另一个选择是创建一个模型类，该类镜像 _MyEntity 而不扩展 ManagedObject:

class MyEntityModel implements _MyEntity {
  @override
  int id;

  @override
  int myValue;
}

然后可以在实际插入数据库时​​将其映射到 MyEntity。安装测试工具并直接使用 MyEntity 似乎更好，这就是我所做的。

有关设置测试的更多帮助，请参阅 this video和 documentation .