在测试类中使用mockito模拟新实例的创建

public class UserService {
    private UserRepository userRepository;

    public UserService(UserRepository userRepository) {
        this.userRepository = userRepository;
    }

    public User getUserById(String id) {
        return userRepository.findById(id);
    }
}

import static org.mockito.Mockito.*;
import static org.junit.jupiter.api.Assertions.*;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;

public class UserServiceTest {

    @Mock
    private UserRepository userRepository;

    @InjectMocks
    private UserService userService;

    @BeforeEach
    public void setUp() {
        MockitoAnnotations.openMocks(this);
    }

    @Test
    public void testGetUserById() {
        // 创建一个模拟的 User 对象
        User mockUser = new User("1", "John Doe");

        // 设置模拟对象的行为
        when(userRepository.findById("1")).thenReturn(mockUser);

        // 调用被测方法
        User result = userService.getUserById("1");

        // 验证结果
        assertEquals(mockUser, result);

        // 验证方法调用
        verify(userRepository).findById("1");
    }
}

when(userRepository.findById("1")).thenReturn(mockUser);

@BeforeEach
public void setUp() {
    MockitoAnnotations.openMocks(this);
}