i got a 'testsuitename' and 'testcasename' has not been declared when i use FRIEND_TEST macro

[git45016683]

Describe the bug

gtest version:1.8.1
i got a 'testsuitename' and 'testcasename' has not been declared when i use FRIEND_TEST macro to test my private code. just like
testing-private-code

Steps to reproduce the bug

code just for demo
i declared a calculate code
`#ifndef CACL_H
#define CALC_H

#include
using namespace std;

#define PRIVATE_METHOD_TEST 0

class Calculate {
public:
Calculate() {}
~Calculate() {}
int calculate(int a, int b, string symbol);

private:
#if PRIVATE_METHOD_TEST
FRIEND_TEST(addTest, privateINT);
#endif // PRIVATE_METHOD_TEST
int add(int a, int b);
};

#endif // CACL_H`

and It‘s implementation
`#include "cacl.h"
#include <stdio.h>

int Calculate::calculate(int a, int b, string symbol)
{
if (symbol == "+")
{
return add(a, b);
} else if (symbol == "-")
{
return sub(a, b);
} else if (symbol == "*")
{
return mul(a, b);
} else if (symbol == "/")
{
return div(a, b);
} else
{
printf("error symbol\r\n");
return -999999;
}
return -999999;
}

int Calculate::add(int a, int b)
{
return a + b;
}
`

and define its unittest in another files
`#include "test_Calculate.h"

TEST(addTest, normalINT)
{
string operate = "+";
Calculate cal;
EXPECT_EQ(cal.calculate(6, 6, operate), 12);
}

#if PRIVATE_METHOD_TEST
TEST(addTest, privateINT)
{
Calculate cal;
EXPECT_EQ(cal.add(6, 6), 12);
}
#endif // PRIVATE_METHOD_TEST`

if PRIVATE_METHOD_TEST is zero ,the unittest is pass(only one unittest),
but is PRIVATE_METHOD_TEST is nonzero, the unittest will failed, will got a 'addTest' and 'privateINT' has not been declared.

you can got complete demo sulotion from unittestWithGtest

Does the bug persist in the most recent commit?

because company just use c++98 and pre-vs2010, only can use gtest version:1.8.1(pre c++11).

What operating system and version are you using?

Redflag and uos and kylin [ both of them are Linux ]

What compiler and version are you using?

g++

What build system are you using?

Makefile and make

Additional context

i learn googletest from here, it will better if there have any sample for test private code .
thansk.

[git45016683]

if want to use FRIENT_TEST macro，need include the head file gtest_prod.h
#include "gtest/gtest_prod.h"