c++ - 如何使用谷歌模拟模拟宏功能

Question

我需要模拟在 linux 头文件中定义的宏:

#include <asm/types.h>
#include <linux/netlink.h>

for (msg_ptr = (struct nlmsghdr *) reply; 
     NLMSG_OK(msg_ptr, len); 
     msg_ptr = NLMSG_NEXT(msg_ptr, len))
{
   // do something
}

NLMSG_OK 在一些 linux 头文件 linux/netlink.h 中定义。

如何使用 google mock 模拟它？

google mock 是否支持模拟宏？

Answer 1

How to mock it using google mock?

你不能。

Does google mock support mocking macro?

没有。

首先，宏不是函数!它们只是从预处理阶段扩展而来的文本处理模板。

好吧，我们假设宏以某种方式扩展为全局函数调用，他们在 FAQ 中给出了以下答案:

My code calls a static/global function. Can I mock it?

You can, but you need to make some changes.

In general, if you find yourself needing to mock a static function, it's a sign that your modules are too tightly coupled (and less flexible, less reusable, less testable, etc). You are probably better off defining a small interface and call the function through that interface, which then can be easily mocked. It's a bit of work initially, but usually pays for itself quickly.

This Google Testing Blog post says it excellently. Check it out

---

关于您的评论“您使用#undef 和重新#define 是什么意思？”:

我的意思是您需要使用自己的宏定义来编译被测代码，这会注入(inject)一个 Google Mock 类/函数。

#if defined(UNDER_TEST)
#undef NLMSG_OK
#define NLMSG_OK(msg_ptr, len) \
     // your mocking code
#endif