Golang 测试中如何处理依赖项_Golang Mock 对象与接口注入实战

type User struct {
    ID   int
    Name string
}

type UserRepository interface {
    FindByID(id int) (*User, error)
}

type UserService struct {
    repo UserRepository
}

func NewUserService(repo UserRepository) *UserService {
    return &UserService{repo: repo}
}

func (s *UserService) GetUserName(id int) (string, error) {
    user, err := s.repo.FindByID(id)
    if err != nil {
        return "", err
    }
    return user.Name, nil
}

type MockUserRepository struct {
    users map[int]*User
}

func (m *MockUserRepository) FindByID(id int) (*User, error) {
    if user, exists := m.users[id]; exists {
        return user, nil
    }
    return nil, fmt.Errorf("user not found")
}

func TestUserService_GetUserName(t *testing.T) {
    mockRepo := &MockUserRepository{
        users: map[int]*User{
            1: {ID: 1, Name: "Alice"},
        },
    }

    service := NewUserService(mockRepo)

    name, err := service.GetUserName(1)
    if err != nil {
        t.Fatalf("expected no error, got %v", err)
    }
    if name != "Alice" {
        t.Errorf("expected Alice, got %s", name)
    }
}

go install github.com/vektra/mockery/v2@latest

//+mockery:generate
type UserRepository interface {
    FindByID(id int) (*User, error)
}