問題描述

我有以下代碼要進(jìn)行單元測試:

I have the following code to be unit tested:

public void foo() {
    Entity entity = //...
    persistence.save(entity);
    entity.setDate(new Date());
    persistence.save(entity);
}

我想驗(yàn)證在第一次調(diào)用 persistence.save entity.getDate() 時(shí)返回 null.

I would like to verify that on the first invocation of persistence.save entity.getDate() returns null.

因此我無法使用 Mockito.verify(/*...*/) 因?yàn)楫?dāng)時(shí)方法 foo 已經(jīng)完成并且 entity.setDate(Date) 被調(diào)用.

Therefore I'm unable to use Mockito.verify(/*...*/) because at that time the method foo already completed and entity.setDate(Date) was called.

所以我認(rèn)為我需要在調(diào)用發(fā)生時(shí)對(duì)調(diào)用進(jìn)行驗(yàn)證.如何使用 Mockito 做到這一點(diǎn)?

So I think I need to do verifications of invocations already at the time the invocations happen. How do I do this using Mockito?

推薦答案

我創(chuàng)建了以下 Answer 實(shí)現(xiàn):

I created the following Answer implementation:

public class CapturingAnswer<T, R> implements Answer<T> {

    private final Function<InvocationOnMock, R> capturingFunction;

    private final List<R> capturedValues = new ArrayList<R>();

    public CapturingAnswer(final Function<InvocationOnMock, R> capturingFunction) {
        super();
        this.capturingFunction = capturingFunction;
    }

    @Override
    public T answer(final InvocationOnMock invocation) throws Throwable {
        capturedValues.add(capturingFunction.apply(invocation));
        return null;
    }

    public List<R> getCapturedValues() {
        return Collections.unmodifiableList(capturedValues);
    }

}

此答案捕獲正在執(zhí)行的調(diào)用的屬性.capturedValues 然后可以用于簡單的斷言.該實(shí)現(xiàn)使用 Java 8 API.如果這不可用，則需要使用能夠?qū)?InvocationOnMock 轉(zhuǎn)換為捕獲值的接口.測試用例中的用法是這樣的:

This answer captures properties of the invocations being made. The capturedValues can then be used for simple assertions. The implementation uses Java 8 API. If that is not available one would need to use an interface that is able to convert the InvocationOnMock to the captured value. The usage in the testcase is like this:

@Test
public void testSomething() {
    CapturingAnswer<Void,Date> captureDates = new CapturingAnswer<>(this::getEntityDate)
    Mockito.doAnswer(captureDates).when(persistence).save(Mockito.any(Entity.class));

    service.foo();

    Assert.assertNull(captureDates.getCapturedValues().get(0));
}

private Date getEntityDate(InvocationOnMock invocation) {
    Entity entity = (Entity)invocation.getArguments()[0];
    return entity.getDate();
}

使用 Mockitos ArgumentCaptor 無法實(shí)現(xiàn)由呈現(xiàn)的 Answer 實(shí)現(xiàn)完成的捕獲，因?yàn)檫@僅在調(diào)用被測方法后使用.

The capturing that is done by the presented Answer implementation can't be achieved with Mockitos ArgumentCaptor because this is only used after the invocation of the method under test.

這篇關(guān)于如何使用相同的參數(shù)驗(yàn)證對(duì)同一模擬方法的調(diào)用，該參數(shù)在模擬中的調(diào)用之間改變狀態(tài)?的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！