安卓测试 : use Dagger2 + Gradle

Question

我了解 Dagger2 的工作原理，

我知道它允许轻松交换依赖关系，因此我们可以使用模拟进行测试。

重点是我不确定我是否理解我应该如何为测试和调试/生产提供不同的 Dagger2 组件实现。

我是否需要创建 2 个 Gradle productFlavors(例如“Production”/“Test”)那将包含 2 个不同的组件定义？

或者我可以指定我想使用模拟组件进行测试编译，使用非模拟组件进行非测试构建吗？

我很困惑，请澄清一下就好了!

非常感谢!

Answer 1

单元测试

Don’t use Dagger for unit testing

要用@Inject 注释的构造函数测试类，您不需要 Dagger 。而是使用具有虚假或模拟依赖项的构造函数创建一个实例。

final class ThingDoer {
  private final ThingGetter getter;
  private final ThingPutter putter;

  @Inject ThingDoer(ThingGetter getter, ThingPutter putter) {
    this.getter = getter;
    this.putter = putter;
  }

  String doTheThing(int howManyTimes) { /* … */ }
}

public class ThingDoerTest {
  @Test
  public void testDoTheThing() {
    ThingDoer doer = new ThingDoer(fakeGetter, fakePutter);
    assertEquals("done", doer.doTheThing(5));
  }
}

功能/集成/端到端测试

Functional/integration/end-to-end tests typically use the production application, but substitute fakes[^fakes-not-mocks] for persistence, backends, and auth systems, leaving the rest of the application to operate normally. That approach lends itself to having one (or maybe a small finite number) of test configurations, where the test configuration replaces some of the bindings in the prod configuration.

这里有两个选择:

选项 1:通过子类化模块覆盖绑定(bind)

    @Component(modules = {AuthModule.class, /* … */})
    interface MyApplicationComponent { /* … */ }

    @Module
    class AuthModule {
      @Provides AuthManager authManager(AuthManagerImpl impl) {
        return impl;
      }
    }

    class FakeAuthModule extends AuthModule {
      @Override
      AuthManager authManager(AuthManagerImpl impl) {
        return new FakeAuthManager();
      }
    }

    MyApplicationComponent testingComponent = DaggerMyApplicationComponent.builder()
        .authModule(new FakeAuthModule())
        .build();

选项 2:单独的组件配置

@Component(modules = {
  OAuthModule.class, // real auth
  FooServiceModule.class, // real backend
  OtherApplicationModule.class,
  /* … */ })
interface ProductionComponent {
  Server server();
}

@Component(modules = {
  FakeAuthModule.class, // fake auth
  FakeFooServiceModule.class, // fake backend
  OtherApplicationModule.class,
  /* … */})
interface TestComponent extends ProductionComponent {
  FakeAuthManager fakeAuthManager();
  FakeFooService fakeFooService();
}

在 official documentation testing page 中了解更多信息.