java - 谷歌指南 : Mock a @provides method consists of set of object

Question

我有一个 A 类，它将一个集合作为 guice 依赖项。该集合是单例的。下面是代码示例:

class A
{
   private Set<InetAddress> set;
   private String pingUriPath;
   @Inject
   public A(Set<InetAddress> set, @Named("pingUri") String pingUriPath)
        {
          this.set = set;
          this.pingUriPath = pingUriPath; // this is used somewhere
        }

   public void storeValue(String str)
   {
      if(str.equals("abc"))
       {
          set.add(str);
       }
   }

}

这里是注入(inject)依赖的guice模块:

private class GuiceModule extends AbstractModule {
        @Override
        public void configure() {
          bindConstant().annotatedWith(Names.named("pingUri")).to("/ping");
        }

        @Provides
        @Singleton
        Set<InetAddress> healthyTargets(){
            return Sets.newConcurrentHashSet();
        }
    }

我想模拟 storeValue 方法，为此我必须模拟集合。我无法使用 guice 模拟集合。 如果我像下面这样模拟，它会给出断言错误(与这个模拟没有交互)

@Mock
Set<InetAddress> mockHealthyTargets;

private class MockClassesModule extends AbstractModule {
        @Override
        public void configure() {
            bindConstant().annotatedWith(Names.named("pingUri")).to("/ping");
        }

        @Provides
        @Singleton
        Set<InetAddress> healthyTargets(){
            return Sets.newConcurrentHashSet();
        }
    }

public test_storeValue()
{
   Injector injector = Guice.createInjector(new MockClassesModule());
   A a = injector.getInstance(A.class);
   a.storeValue("abc");
   verify(mockHealthyTargets).add("abc")
}

Answer 1

如果您需要在单元测试中使用 guice，那么很可能是方向错误。依赖项注入(inject)的最大好处之一是测试变得容易，因为您可以传递由您控制的依赖项。

我假设您想测试类 A，特别是方法 storeValue。为此你甚至不需要模拟

@Test
public void test() {
    // prepare dependencies
    Set<InetAddress> set = Sets.newConcurrentHashSet(); 
    String pingUri = "example.com";

    // prepare input
    String input = "someValue";

    // prepare class under test
    A classUnderTest = new A(set, pingUri);

    // call class under test
    classUnderTest.storeValue(input);

    // check that what you expected happened
    // in this case you expect that the dependency set now contains the input
    assertThat(set, contains(input));
}