e_pattern</em></span> facilitates switching mode of
          operation for testing output streams. See <a class="link" href="../../testing_tools/output_stream_testing.html" title="Output streams testing tool">output
          test stream</a> section for details on these tests.
        </p>
<p>
          This parameter serves no particular purpose within the framework itself.
          It can be used by test modules relying on <code class="computeroutput"><a class="link" href="../../../boost/test_tools/outp