a><span class="special">(</span><span class="keyword">bool</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">)</span><span class="special">;</span>
  <span class="keyword">virtual</span> <a class="link" href="assertion_result.html" title="Class assertion_result">assertion_result</a> <a class="link" href="output_test_stream.html#idp41328976-bb"><span class="identifier">check_length</span></a><span class="special">(</span><span class="identifier">std</span><span clas