expression is
        constructed from the <code class="computeroutput"><span class="identifier">statement</span></code>
        appearing in the <code class="computeroutput"><span class="identifier">BOOST_TEST</span></code>
        macro. This expression allows evaluation and reporting such as <code class="computeroutput"><span class="string">"13 - 1 &gt;= 12"</span> <span class="identifier">failed</span></code>
        along with a copy of the <code class="computeroutput"><span class="identifier">statemen