// ProductService 商品服務(wù)接口（抽象依賴）
type ProductService interface {
    GetProduct(id string) (*Product, error)   // 獲取商品
    UpdateStock(id string, num int) error     // 更新庫存
}

// PaymentService 支付服務(wù)接口（抽象依賴）
type PaymentService interface {
    ProcessPayment(amount float64, orderID string) (*PaymentResult, error) // 處理支付
}

// OrderService 被測試的訂單服務(wù)（依賴接口，不依賴具體實現(xiàn)）
type OrderService struct {
    productService ProductService  // 依賴商品服務(wù)接口
    paymentService PaymentService  // 依賴支付服務(wù)接口
}

// MockProductService 商品服務(wù)的Mock實現(xiàn)
type MockProductService struct {
    mock.Mock  // 嵌入testify的Mock結(jié)構(gòu)體，獲得Mock能力
}

// GetProduct 實現(xiàn)ProductService接口的GetProduct方法
func (m *MockProductService) GetProduct(id string) (*Product, error) {
    args := m.Called(id)  // 記錄方法調(diào)用的參數(shù)
    if args.Get(0) == nil {
        return nil, args.Error(1)
    }
    return args.Get(0).(*Product), args.Error(1)
}

// 預(yù)設(shè)"查詢prod1商品"的行為
mockProduct.On("GetProduct", "prod1").Return(testProduct, nil)
// 預(yù)設(shè)"支付服務(wù)未開啟"的行為
mockPayment.On("ProcessPayment", 99.99, mock.Anything).Return(nil, errors.New("支付服務(wù)未開啟"))

// 注入Mock對象
orderService := NewOrderService(mockProduct, mockPayment)

// 調(diào)用被測試方法
order, err := orderService.CreateOrder("prod1", "user1")

// 驗證業(yè)務(wù)結(jié)果
assert.Error(t, err)
assert.Nil(t, order)

// 驗證Mock調(diào)用
mockProduct.AssertExpectations(t)
mockPayment.AssertExpectations(t)

package main

import "github.com/stretchr/testify/mock"

// MockProductService 商品服務(wù)的Mock實現(xiàn)
type MockProductService struct {
    mock.Mock  // 嵌入mock.Mock結(jié)構(gòu)體，繼承核心功能
}

// GetProduct 實現(xiàn)ProductService接口的GetProduct方法
func (m *MockProductService) GetProduct(id string) (*Product, error) {
    args := m.Called(id)  // 記錄方法調(diào)用的參數(shù)
    if args.Get(0) == nil {
        return nil, args.Error(1)
    }
    return args.Get(0).(*Product), args.Error(1)
}

// UpdateStock 實現(xiàn)ProductService接口的UpdateStock方法
func (m *MockProductService) UpdateStock(id string, num int) error {
    args := m.Called(id, num)  // 記錄方法調(diào)用的參數(shù)
    return args.Error(0)  // 返回預(yù)設(shè)的錯誤
}

// MockPaymentService 支付服務(wù)的Mock實現(xiàn)
type MockPaymentService struct {
    mock.Mock  // 嵌入Mock結(jié)構(gòu)體，獲得Mock能力
}

// ProcessPayment 實現(xiàn)PaymentService接口的ProcessPayment方法
func (m *MockPaymentService) ProcessPayment(amount float64, orderID string) (*PaymentResult, error) {
    args := m.Called(amount, orderID)  // 記錄方法調(diào)用的參數(shù)
    if args.Get(0) == nil {
        return nil, args.Error(1)
    }
    return args.Get(0).(*PaymentResult), args.Error(1)
}

package main

import (
    "errors"
    "testing"
    "github.com/stretchr/testify/assert"
)

// TestCreateOrder_PaymentServiceUnavailable 測試支付服務(wù)未開啟場景
func TestCreateOrder_PaymentServiceUnavailable(t *testing.T) {
    // 創(chuàng)建Mock對象
    mockProduct := new(MockProductService)
    mockPayment := new(MockPaymentService)

    // 定義測試數(shù)據(jù)
    testProduct := &Product{
        ID:    "prod1",
        Name:  "測試商品",
        Price: 99.99,
        Stock: 100,
    }
    
    // 預(yù)設(shè)Mock行為
    mockProduct.On("GetProduct", "prod1").Return(testProduct, nil)
    mockProduct.On("UpdateStock", "prod1", -1).Return(nil)
    mockPayment.On("ProcessPayment", 99.99, mock.Anything).Return(nil, errors.New("支付服務(wù)未開啟"))

    // 初始化被測試服務(wù)
    orderService := NewOrderService(mockProduct, mockPayment)
    
    // 調(diào)用被測試方法
    order, err := orderService.CreateOrder("prod1", "user1")

    // 驗證結(jié)果
    assert.Error(t, err)
    assert.Nil(t, order)
    mockProduct.AssertExpectations(t)
    mockPayment.AssertExpectations(t)
}