Mockito和Hamcrest：如何验证Collection参数的调用？ [英] Mockito and Hamcrest: how to verify invocation of Collection argument?

问题描述

请假设以下界面：

pre> public interface Service {
void perform（Collection< String> elements）;
}


以下是测试片段：

  Service service = mock（Service.class）; 
 $ b $ //执行业务逻辑
 
验证（服务）.perform（Matchers.argThat（contains（a，b）））; 
  

所以我想验证一下我的业务逻辑实际上是用一个包含a和b。

但是，的返回类型包含（...）为匹配器<可迭代< ;?扩展E>> ，所以 Matchers.argThat（...）返回 Iterable< String> 在我的情况下，这自然不适用于所需的集合< String> 。

我知道我可以使用参数捕获器，如 Hamcrest hasItem和Mockito验证不一致 ，但我非常想不要。

有任何建议！
Thanks！

解决方案

您可以写出

<$ p验证（服务）.perform（（集合< String>）Matchers.argThat（contains（a，b）））;

从编译器的角度来看，这是铸造一个 Iterable< String> 到集合< String> 这很好，因为后者是前者的子类型。在运行时， argThat 将返回 null ，所以可以传递给执行没有 ClassCastException 。关于它的重要一点是，匹配器进入Mockito的内部验证参数结构，这就是 argThat 所做的。

I'm running into a generics problem with Mockito and Hamcrest.

Please assume the following interface:

public interface Service {
    void perform(Collection<String> elements);
}

And the following test snippet:

Service service = mock(Service.class);

// ... perform business logic

verify(service).perform(Matchers.argThat(contains("a", "b")));

So I want to verify that my business logic actually called the service with a collection that contains "a" and "b" in that order.

However, the return type of contains(...) is Matcher<Iterable<? extends E>>, so Matchers.argThat(...) returns Iterable<String> in my case, which naturally does not apply to the required Collection<String>.

I know that I could use an argument captor as proposed in Hamcrest hasItem and Mockito verify inconsistency, but I would very much like not to.

Any suggestions! Thanks!

解决方案

You can just write

verify(service).perform((Collection<String>) Matchers.argThat(contains("a", "b")));

From the compiler's point of view, this is casting an Iterable<String> to a Collection<String> which is fine, because the latter is a subtype of the former. At run time, argThat will return null, so that can be passed to perform without a ClassCastException. The important point about it is that the matcher gets onto Mockito's internal structure of arguments for verification, which is what argThat does.

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