</span><span class="special">()</span> <span class="keyword">const</span>   <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">iterator</span><span class="special">();</span> <span class="special">}</span>
<span class="special">};</span>

<span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">unit_test</span> <span class="special">{</span> <span class=