hypothetical test project file:</p>

<div class="code"><pre class="prettyprint">&lt;NUnitProject&gt;
  &lt;Settings activeconfig="Debug"/&gt;
  &lt;Config name="Debug"&gt;
    &lt;assembly path="LibraryCore\bin\Debug\Library.dll"/&gt;
    &lt;assembly path="LibraryUI\bin\Debug\LibraryUI.dll"/&gt;
  &lt;/Config&gt;
  &lt;Config name="Release"&gt;
    &lt;assembly path="LibraryCore\bin\Release\Library.dll"/&gt;
    &lt;assembly path="LibraryUI\bin\Release\LibraryUI.dll"/&gt;
  &lt;/Config&gt;
&lt;/NUnitProjec