java 如何使用 Mockito 和 jUnit 模拟持久化和实体
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How to mock persisting and Entity with Mockito and jUnit
提问by Patrick
I'm trying to find a way to test my entity using Mockito;
我正在尝试找到一种使用 Mockito 测试我的实体的方法；
This is the simple test method:
这是简单的测试方法：
@Mock
private EntityManager em;
@Test
public void persistArticleWithValidArticleSetsArticleId() {
Article article = new Article();
em.persist(article);
assertThat(article.getId(), is(not(0L)));
}
How do I best mock the behaviour that the EntityManager changes the Id from 0L to i.e. 1L? Possibly with the least obstructions in readability.
我如何最好地模拟 EntityManager 将 Id 从 0L 更改为 1L 的行为？可能对可读性的阻碍最小。
Edit: Some extra information; Outside test-scope the EntityManager is produced by an application-container
编辑：一些额外的信息；在测试范围之外，EntityManager 由应用程序容器生成
回答by Dawood ibn Kareem
You could use a Mockito Answerfor this.
您可以Answer为此使用 Mockito 。
doAnswer(new Answer<Object>(){
@Override
public Object answer(InvocationOnMock invocation){
Article article = (Article) invocation.getArguments()[0];
article.setId(1L);
return null;
}
}).when(em).persist(any(Article.class));
This tells Mockito that when the persistmethod is called, the first argument should have its setIdmethod invoked.
这告诉 Mockito 当persist方法被调用时，第一个参数应该setId调用它的方法。
But if you do this, I don't understand what the purpose of the test would be. You'd really just be testing that the Mockito Answermechanism works, not that the code of Articleor of EntityManagerworks correctly.
但是如果你这样做，我不明白测试的目的是什么。您实际上只是在测试 MockitoAnswer机制是否有效，而不是Article或的代码EntityManager是否正常工作。
回答by JB Nizet
public class AssignIdToArticleAnswer implements Answer<Void> {
private final Long id;
public AssignIdToArticleAnswer(Long id) {
this.id = id;
}
@Override
public Void answer(InvocationOnMock invocation) throws Throwable {
Article article = (Article) invocation.getArguments()[0];
article.setId(id);
return null;
}
}
And then
接着
doAnswer(new AssignIdToArticleAnswer(1L)).when(em).persist(any(Article.class));
回答by gmode
similar answer as above, but with lambdas
与上面类似的答案，但使用 lambdas
doAnswer((InvocationOnMock invocation) -> {
Article article = (Article) invocation.getArguments()[0];
article.setId(1L);
return null;
}).when(em).persist(any(Article.class));
