Boost C++ Libraries: Ticket #12876: BOOST_CHECK_EQUAL fail for vector with operator<< for vector

401819174@… — Wed, 01 Mar 2017 02:44:34 GMT

BOOST_AUTO_TEST_CASE(test_print_vector_int) {

const std::vector<int> a{1};

const std::vector<int> b{2};

std::cout << a << std::endl; /* work */

BOOST_CHECK_EQUAL(a, b); /* don't work. */

/* error: static assertion failed: Type has to implement operator<< to be printable */

/* std::cout << boost::has_left_shift<std::ostream, vector<int>>::value << endl;*/

/* use user define class is ok */

std::vector<PrintClass> c{PrintClass()}; std::vector<PrintClass> d{PrintClass()}; std::cout << c << std::endl; /* work */ BOOST_CHECK_EQUAL(c, d); /* work */

}

status changed; resolution set

Raffi Enficiaud — Wed, 01 Mar 2017 11:31:08 GMT

status new → closed
resolution → invalid

You have BOOST_CHECK_EQUAL_COLLECTIONS or BOOST_TEST that works on collections as well.

If the underlying type is not printable, then you should consider using BOOST_TEST_DONT_PRINT_LOG_VALUE

Best, Raffi

401819174@… — Thu, 02 Mar 2017 03:10:21 GMT

thank you

the C++ function overload mechanism require all overload function in the same domain. vector/int, make search the function from std or boost::*(boost::has_left_shift). in the std has the define of operator<<, so in the global define of operator<< is not visiable。

Raffi Enficiaud — Thu, 02 Mar 2017 08:07:11 GMT

I do not understand everything you are saying (please use the Wiki Markup), but here is what I think:

const std::vector<int> a{1};
const std::vector<int> b{2};
BOOST_CHECK_EQUAL(a, b); /* does not work. */

This does not work because it requires std::vector<int> to be printable, which is usually never the case by default. However

BOOST_CHECK_EQUAL_COLLECTIONS(a.begin(), a.end(), b.begin(), b.end());

works as expected, because the underlying int is already printable.

Concerning

std::vector<PrintClass> c{PrintClass()};
std::vector<PrintClass> d{PrintClass()};
BOOST_CHECK_EQUAL(c, d);

In your example, this works because you have this template that is capture the prints to std::cout:

template <typename T> std::ostream & operator<< (
    std::ostream & os,
    std::vector<T> const &v)

Your bug is invalid.