Re: [Boost-users] [test] how to test std::pair with BOOST_TEST

Subject: Re: [Boost-users] [test] how to test std::pair with BOOST_TEST
From: Edward Diener (eldiener_at_[hidden])
Date: 2016-05-29 14:39:23

On 5/29/2016 10:36 AM, ttan wrote:
> Edward Diener-3 wrote
>> On 5/29/2016 8:10 AM, Tan, Tom (Shanghai) wrote:
>>> The following snippet does not compile with VS2015 and boost 1.61. What
>>> should the correct way to do it? Thanks.
>>>
>>>>
>>> // compile with cl.exe /EHSc
>>>
>>> #define BOOST_TEST_MODULE pair
>>>
>>> #include <boost/test/included/unit_test.hpp>
>>>
>>>
>>>
>>> std::pair<uint32_t, uint32_t> v()
>>>
>>> {
>>>
>>>     return std::make_pair(0, 0);
>>>
>>> }
>>>
>>> BOOST_AUTO_TEST_CASE(range)
>>>
>>> {
>>>>     BOOST_TEST(std::make_pair(0, 0) == v());
>>>> }
>>>
>>>
>>
>> std::make_pair(0,0) returns a value with the type std::pair<int,int>
>> whereas v() returns a variable of the type
>> std::pair<uint32_t,uint32_t>.
>> These are different types and there is no equality operator to compare
>> them.
>
> Thanks, my code above is misleading. Iwas actually intended to illustrate
> the support of std::pair by BOOST_TEST, like below
>
> BOOST_AUTO_TEST_CASE(range)
> {
>     (std::make_pair(uint32_t(0), uint32_t(0)) == v());  // this is OK
>     BOOST_TEST(std::make_pair(uint32_t(0), uint32_t(0)) == v()); // this not
> }
>
> judging from the error, operator << is not support by std::pair in
> boost.test. What is the best way, I mean where, to add the support?

Something like:

#include <ostream>

template<typename T>
std::ostream & operator << (std::ostream & os,const std::pair<T,T> & pr)
{
os << pr.first << ' ' << pr.second;
}

Look up "C++ writing output operator" on the Internet.

>
> C:\3rd\boost_1_61_0\boost/test/tools/detail/print_helper.hpp(47): error
> C2338: Type has to implement operator<< to be printable