航旅旺季前零 P1 上线：Virgin Atlantic 用 Codex 把测试覆盖率拉到近乎满分

# booking.py — 航旅订票核心逻辑（简化示例）

class BookingService:
    def __init__(self, inventory, pricing):
        self.inventory = inventory
        self.pricing = pricing

    def book(self, flight_id, passenger_count, cabin_class):
        """订票：检查库存、计算价格、扣减座位"""
        available = self.inventory.get_available(flight_id, cabin_class)
        if available < passenger_count:
            raise ValueError(f"座位不足: 需要 {passenger_count}, 可用 {available}")

        price = self.pricing.calculate(flight_id, cabin_class, passenger_count)
        self.inventory.decrease(flight_id, cabin_class, passenger_count)
        return {"flight_id": flight_id, "passengers": passenger_count,
                "cabin": cabin_class, "total_price": price}

# generate_tests.py — 批量生成单元测试骨架

import openai
import inspect

def generate_tests(source_code: str, module_name: str) -> str:
    """调用 OpenAI 为给定源码生成 pytest 测试"""
    prompt = f"""你是一位资深 Python 测试工程师。
请为以下模块编写完整的 pytest 单元测试，要求：
1. 覆盖正常路径和所有异常路径
2. 使用 mock 替换外部依赖（inventory, pricing）
3. 每个测试函数名清晰表达测试意图
4. 包含边界值测试

模块名: {module_name}
源码:
```python
{source_code}
```"""

    response = openai.chat.completions.create(
        model="gpt-4o",
        messages=[{"role": "user", "content": prompt}],
        temperature=0.2,  # 低温度保证输出稳定可复现
    )
    return response.choices[0].message.content

# ——— 主流程：读取源码 → 生成测试 → 写入文件 ———
if __name__ == "__main__":
    from booking import BookingService

    source = inspect.getsource(BookingService)
    test_code = generate_tests(source, "booking")

    # 提取代码块（去除 markdown 包裹）
    lines = test_code.split("\n")
    code_lines = []
    in_block = False
    for line in lines:
        if line.strip().startswith("```python"):
            in_block = True
            continue
        if line.strip() == "```":
            in_block = False
            continue
        if in_block:
            code_lines.append(line)

    with open("test_booking_generated.py", "w") as f:
        f.write("\n".join(code_lines))

    print("测试已写入 test_booking_generated.py，请人工审核后运行 pytest")

# 安装依赖
pip install openai pytest

# 设置 API Key
export OPENAI_API_KEY="sk-..."

# 执行生成
python generate_tests.py

# 审核后运行测试
pytest test_booking_generated.py -v

# test_booking_generated.py — AI 生成、人工审核后的测试

from unittest.mock import MagicMock
import pytest
from booking import BookingService

def test_book_success():
    """正常订票：库存充足，返回完整订单"""
    inventory = MagicMock()
    pricing = MagicMock()
    inventory.get_available.return_value = 10
    pricing.calculate.return_value = 5000.0

    svc = BookingService(inventory, pricing)
    result = svc.book("VS001", 2, "economy")

    assert result["flight_id"] == "VS001"
    assert result["passengers"] == 2
    assert result["total_price"] == 5000.0
    inventory.decrease.assert_called_once_with("VS001", "economy", 2)

def test_book_insufficient_seats():
    """异常路径：座位不足时抛 ValueError"""
    inventory = MagicMock()
    pricing = MagicMock()
    inventory.get_available.return_value = 1  # 低于需求

    svc = BookingService(inventory, pricing)
    with pytest.raises(ValueError, match="座位不足"):
        svc.book("VS001", 5, "economy")

    # 确保未扣减库存
    inventory.decrease.assert_not_called()

def test_book_boundary_exact_capacity():
    """边界值：恰好等于可用座位数"""
    inventory = MagicMock()
    pricing = MagicMock()
    inventory.get_available.return_value = 3
    pricing.calculate.return_value = 7500.0

    svc = BookingService(inventory, pricing)
    result = svc.book("VS001", 3, "economy")
    assert result["passengers"] == 3