[Boost-bugs] [Boost C++ Libraries] #12540: Provide customisation point for printing types in tests

Subject: [Boost-bugs] [Boost C++ Libraries] #12540: Provide customisation point for printing types in tests
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-10-21 17:38:57

#12540: Provide customisation point for printing types in tests
-------------------------------------------------+-------------------------
 Reporter:  Tony Lewis <TonyELewis@…>            |      Owner:  rogeeff
     Type:  Feature Requests                     |     Status:  new
Milestone:  To Be Determined                     |  Component:  test
  Version:  Boost 1.61.0                         |   Severity:
 Keywords:                                       |  Optimization
  test,customization,customisation,output,print,stream,insertion|
  operator,print_log_value,BOOST_TEST_DONT_PRINT_LOG_VALUE|
-------------------------------------------------+-------------------------
 AFAIU (from doc "Logging user defined types"), the current design gives
 users two options for handling output for their types in tests:
  * Provide `operator<<`
  * Prevent printing with `BOOST_TEST_DONT_PRINT_LOG_VALUE()`

 ...and all types must be printed.

 I suggest that this is to rigid. For some types, users may not want to
 provide a global `operator<<`, or they may have already provided an
 `operator<<` or they may not own the type.

 For these reasons, I think it would be better if Boost Test provided an
 explicit customization point that defaulted to calling `operator<<` but
 that could be overridden by the user to explictly control the Test
 printing without affecting `operator<<`.

 In fact, I think `boost::test_tools::tt_detail::print_log_value` is
 already close to serving this purpose and perhaps it needs little more
 than being made part of the public interface and documented.

 Thanks for all your work.


 PS "D4381: Suggested Design for Customization Points" may be relevant
 here.

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Ticket URL: <https://svn.boost.org/trac/boost/ticket/12540>
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