如何在 Mockito 3 中用@InjectMocks 注释的 class 的构造函数中注入最终的 class，例如 String

Question

我想模拟以下 class：

public class MyRunner {
    private String name;
    private User user;//not final
    public MyRunner(String name, User user) {
      this.name = name;
      this.user = user
    }
    //...something complicated in the methods
}

就像使用JMockit

@ExtendWith(MockitoExtension.class)
public class MyRunnerTest {
    @Inject
    private String name = "sth";
    @Inject
    private User user;
    @Tested
    private MyRunner tested;
}

与 Mockito 3 类似，

@ExtendWith(MockitoExtension.class)
public class MyRunnerTest {
    @Mock
    private String name;
    @Mock
    private User user;
    @InjectMocks
    private MyRunner tested;
    @Test //from JUnit5
    public void testSth() {
      //...
    }
}

问题：由于String是最终的 class，在构造过程中将name字符串注入MyRunner会失败。 收到如下错误消息：

Cannot mock/spy class java.lang.String
Mockito cannot mock/spy because :
 - final class

可以使用新关键字初始化测试的 class：

@ExtendWith(MockitoExtension.class)
public class MyRunnerTest {
    private String name = "sth";
    @Mock
    private User user;
    private MyRunner tested = new MyRunner(name, user);
    @Test //from JUnit5
    public void testSth() {
      //...
    }
}

但是，上面的解决方案并不像仅仅使用注解那样流畅

问题：如何将最终的 class注入到带有 @InjectMocks 注释的@InjectMocks中，而不是使用new关键字显式构造它？

Answer 1

有很多方法可以解决这个问题。 这里有3个概念上不同的：

选项1

首先，如果您真的在谈论字符串，那么可能 mocking 它没有多大意义：基本上您的示例根本不需要 mockito 。 您可以简单地：

public class UserTest {
  private final String NAME = "sampleName;

  private User tested = new User(NAME);

 ...
}

选项 2

现在，假设您在这里不是真的在谈论String class，最好的选择是通过创建 Mocks 相当简单的接口进行编程：

public class User {
    public User(Name name) {
      ...
    }

}

public interface Name {
   String getValue();
}

@ExtendsWith(MockitoExtension.class)
public class UserTest

   @Mock
   private Name name;

   @InjectMocks
   private User tested;

选项 3

If you're absolutely required to mock static class, you can do that in mockito but it requires some additional setup: basically you create a file org.mockito.plugins.MockMaker in the directory src/test/resources/mockito-extensions that will包含：

mock-maker-inline

有关更多信息，请参阅本教程