java - stub 具有通用类参数的方法

Question

我正在尝试 stub 以下类:

public class MyFactory {
    ...
    public Publisher getPublisher(String arg1, String arg2, Class<? extends QueueMessage> msgClass) {
        do the magic...
    }
}

这是 Publisher 类的(简短版本):

public class Publisher <M extends QueueMessage> {

    public void publish(M message) throws IOException {
        publish(message);
    } 
}

我想在两种消息的测试中有两个 stub 。这是 stub 代码:

@Mock
private Factory factory;

@Mock
protected ThisMessagePublisher<ThisMessageType> thisMessagePublisher;

@Mock
protected ThatMessagePublisher<ThatMessageType> thatMessagePublisher;

when(factory.getPublisher(anyString(), anyString(), isA(ThisMessageType.class.getClass()))).thenReturn(thisMessagePublisher);
when(factory.getPublisher(anyString(), anyString(), isA(ThatMessageType.class.getClass()))).thenReturn(thatMessagePublisher);

编译正确。

然后我尝试调用工厂和两个发布者，希望为每个发布者验证一个调用。

Publisher thisPublisher = factory.getPublisher("arg1", "arg2", ThisMessageType.class);
thisPublisher.publish(new ThisMessageType("Message"));
Publisher thatPublisher = factory.getPublisher("arg1", "arg2", ThatMessageType.class);
thatPublisher.publish(new ThatMessageType("Message"));

verify(thisPublisher).publish(Matchers.<ThisMessageType>any());
verify(thatPublisher).publish(Matchers.<ThatMessageType>any());

测试失败，出现以下错误:

Wanted but not invoked:
thisPublisher.publish(
    <any>
);
-> at ...
Actually, there were zero interactions with this mock.

显然，第二个 stub 覆盖了第一个 stub 。

深入isA() 代码并调试显示，内部泛型在 stub /调用/编译过程中丢失。挠我的脑后，我似乎想起了一些关于 Java 无法像那样处理内部泛型的事情。

所以我尝试用argThat() stubbing factory，如下，但是结果还是和上面一样的错误。

when(Factory.getPublisher(anyString(), anyString(), argThat(new CustomTypeSafeMatcher<Class<ThisMessageType>>("Is class of ThisMessageType") {
    @Override
    protected boolean matchesSafely(Class<ThisMessageType> aClass) {
        return aClass != null;
    }
}))).thenReturn(thisPublisher);
when(Factory.getPublisher(anyString(), anyString(), argThat(new CustomTypeSafeMatcher<Class<ThatMessageType>>("Is class of ThatMessageType") {
    @Override
    protected boolean matchesSafely(Class<ThatMessageType> aClass) {
        return aClass != null;
    }
}))).thenReturn(thatPublisher);

有什么方法可以实现我想要的 stub 和验证。如果可以，如何实现？

Answer 1

问题出在不正确的匹配器中:

isA(ThisMessageType.class.getClass())

替换为

eq(ThisMessageType.class)

参见 matchers api了解详情。