JMockit - returnsFirstArg equivalent

Question

我必须使用jmockit模拟一个方法，该方法返回与我传递的参数相同的参数。对于Mockito，我使用了AdditionalAnswers.returnsFirstArg:

PowerMockito.when(entityManager.merge((Request)Mockito.any())).then(AdditionalAnswers.returnsFirstArg());

我如何用jmockit写这个？

new Expectations() {
        {
            entityManager.merge((Request) any);
            returns(????);
        }
    };

Answer 1

JMockit没有现成的功能，但它可以很容易地实现，有一个可重用的Delegate类：

class FirstArgument implements Delegate<Object> {
    Object delegate(Invocation inv) { return inv.getInvokedArguments()[0]; }
}
@Mocked EntityManager entityManager;
@Test
public void expectationRecordedToReturnAnArgument()
{
    new Expectations() {{
        entityManager.merge(any);
        result = new FirstArgument();
    }};
    // From the code under test:
    EntityClass entity = new EntityClass();
    EntityClass merged = entityManager.merge(entity);
    assertSame(entity, merged);
}