<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">


<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    
    <title>Sentinel &mdash; Mock 1.0.0 documentation</title>
    
    <link rel="stylesheet" href="_static/nature.css" type="text/css" />
    <link rel="stylesheet" href="_static/pygments.css" type="text/css" />
    
    <script type="text/javascript">
      var DOCUMENTATION_OPTIONS = {
        URL_ROOT:    '',
        VERSION:     '1.0.0',
        COLLAPSE_INDEX: false,
        FILE_SUFFIX: '.html',
        HAS_SOURCE:  true
      };
    </script>
    <script type="text/javascript" src="_static/jquery.js"></script>
    <script type="text/javascript" src="_static/underscore.js"></script>
    <script type="text/javascript" src="_static/doctools.js"></script>
    <link rel="top" title="Mock 1.0.0 documentation" href="index.html" />
    <link rel="next" title="Mocking Magic Methods" href="magicmock.html" />
    <link rel="prev" title="Helpers" href="helpers.html" /> 
  </head>
  <body>
    <div class="related">
      <h3>Navigation</h3>
      <ul>
        <li class="right" style="margin-right: 10px">
          <a href="genindex.html" title="General Index"
             accesskey="I">index</a></li>
        <li class="right" >
          <a href="magicmock.html" title="Mocking Magic Methods"
             accesskey="N">next</a> |</li>
        <li class="right" >
          <a href="helpers.html" title="Helpers"
             accesskey="P">previous</a> |</li>
        <li><a href="index.html">Mock 1.0.0 documentation</a> &raquo;</li> 
      </ul>
    </div>  

    <div class="document">
      <div class="documentwrapper">
        <div class="bodywrapper">
          <div class="body">
            
  <div class="section" id="sentinel">
<h1>Sentinel<a class="headerlink" href="#sentinel" title="Permalink to this headline">¶</a></h1>
<dl class="data">
<dt id="mock.sentinel">
<tt class="descname">sentinel</tt><a class="headerlink" href="#mock.sentinel" title="Permalink to this definition">¶</a></dt>
<dd><p>The <tt class="docutils literal"><span class="pre">sentinel</span></tt> object provides a convenient way of providing unique
objects for your tests.</p>
<p>Attributes are created on demand when you access them by name. Accessing
the same attribute will always return the same object. The objects
returned have a sensible repr so that test failure messages are readable.</p>
</dd></dl>

<dl class="data">
<dt id="mock.DEFAULT">
<tt class="descname">DEFAULT</tt><a class="headerlink" href="#mock.DEFAULT" title="Permalink to this definition">¶</a></dt>
<dd><p>The <cite>DEFAULT</cite> object is a pre-created sentinel (actually
<cite>sentinel.DEFAULT</cite>). It can be used by <a class="reference internal" href="mock.html#mock.Mock.side_effect" title="mock.Mock.side_effect"><tt class="xref py py-attr docutils literal"><span class="pre">side_effect</span></tt></a>
functions to indicate that the normal return value should be used.</p>
</dd></dl>

<div class="section" id="sentinel-example">
<h2>Sentinel Example<a class="headerlink" href="#sentinel-example" title="Permalink to this headline">¶</a></h2>
<p>Sometimes when testing you need to test that a specific object is passed as an
argument to another method, or returned. It can be common to create named
sentinel objects to test this. <cite>sentinel</cite> provides a convenient way of
creating and testing the identity of objects like this.</p>
<p>In this example we monkey patch <cite>method</cite> to return
<cite>sentinel.some_object</cite>:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">&gt;&gt;&gt; </span><span class="n">real</span> <span class="o">=</span> <span class="n">ProductionClass</span><span class="p">()</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">real</span><span class="o">.</span><span class="n">method</span> <span class="o">=</span> <span class="n">Mock</span><span class="p">(</span><span class="n">name</span><span class="o">=</span><span class="s">&quot;method&quot;</span><span class="p">)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">real</span><span class="o">.</span><span class="n">method</span><span class="o">.</span><span class="n">return_value</span> <span class="o">=</span> <span class="n">sentinel</span><span class="o">.</span><span class="n">some_object</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">result</span> <span class="o">=</span> <span class="n">real</span><span class="o">.</span><span class="n">method</span><span class="p">()</span>
<span class="gp">&gt;&gt;&gt; </span><span class="k">assert</span> <span class="n">result</span> <span class="ow">is</span> <span class="n">sentinel</span><span class="o">.</span><span class="n">some_object</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">sentinel</span><span class="o">.</span><span class="n">some_object</span>
<span class="go">sentinel.some_object</span>
</pre></div>
</div>
</div>
</div>


          </div>
        </div>
      </div>
      <div class="sphinxsidebar">
        <div class="sphinxsidebarwrapper">
  <h3><a href="index.html">Table Of Contents</a></h3>
  <ul>
<li><a class="reference internal" href="#">Sentinel</a><ul>
<li><a class="reference internal" href="#sentinel-example">Sentinel Example</a></li>
</ul>
</li>
</ul>

  <h4>Previous topic</h4>
  <p class="topless"><a href="helpers.html"
                        title="previous chapter">Helpers</a></p>
  <h4>Next topic</h4>
  <p class="topless"><a href="magicmock.html"
                        title="next chapter">Mocking Magic Methods</a></p>
  <h3>This Page</h3>
  <ul class="this-page-menu">
    <li><a href="_sources/sentinel.txt"
           rel="nofollow">Show Source</a></li>
  </ul>
<div id="searchbox" style="display: none">
  <h3>Quick search</h3>
    <form class="search" action="search.html" method="get">
      <input type="text" name="q" />
      <input type="submit" value="Go" />
      <input type="hidden" name="check_keywords" value="yes" />
      <input type="hidden" name="area" value="default" />
    </form>
    <p class="searchtip" style="font-size: 90%">
    Enter search terms or a module, class or function name.
    </p>
</div>
<script type="text/javascript">$('#searchbox').show(0);</script>
        </div>
      </div>
      <div class="clearer"></div>
    </div>
    <div class="related">
      <h3>Navigation</h3>
      <ul>
        <li class="right" style="margin-right: 10px">
          <a href="genindex.html" title="General Index"
             >index</a></li>
        <li class="right" >
          <a href="magicmock.html" title="Mocking Magic Methods"
             >next</a> |</li>
        <li class="right" >
          <a href="helpers.html" title="Helpers"
             >previous</a> |</li>
        <li><a href="index.html">Mock 1.0.0 documentation</a> &raquo;</li> 
      </ul>
    </div>
    <div class="footer">
        &copy; Copyright 2007-2012, Michael Foord &amp; the mock team.
      Last updated on Oct 07, 2012.
      Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.1.3.
    </div>
  </body>
</html>