[boost] [Test] XX_MESSAGE and evaluation of arguments

Hi Gennadiy, When I use macros such as BOOST_CHECK_MESSAGE( !evidence, "update evidence = " << withEvidenceUpdate << ", evidence = " << *evidence ); it annoys me that the second argument is evaluated even when the test should pass. In the case above, evidence is an optional<int>. It would be cool if the construction of the error messsage could be delayed until it was actually needed, to make the above scenario valid. Do you think that is possible? Thanks -Thorsten