Edit File: test.html
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Development Tools</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="module-test"> <h1>25.5. <tt class="xref docutils literal"><span class="pre">test</span></tt> — Regression tests package for Python<a class="headerlink" href="#module-test" title="Permalink to this headline">¶</a></h1> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">The <tt class="xref docutils literal"><span class="pre">test</span></tt> package is meant for internal use by Python only. It is documented for the benefit of the core developers of Python. Any use of this package outside of Python’s standard library is discouraged as code mentioned here can change or be removed without notice between releases of Python.</p> </div> <p>The <tt class="xref docutils literal"><span class="pre">test</span></tt> package contains all regression tests for Python as well as the modules <tt class="xref docutils literal"><span class="pre">test.test_support</span></tt> and <tt class="xref docutils literal"><span class="pre">test.regrtest</span></tt>. <tt class="xref docutils literal"><span class="pre">test.test_support</span></tt> is used to enhance your tests while <tt class="xref docutils literal"><span class="pre">test.regrtest</span></tt> drives the testing suite.</p> <p>Each module in the <tt class="xref docutils literal"><span class="pre">test</span></tt> package whose name starts with <tt class="docutils literal"><span class="pre">test_</span></tt> is a testing suite for a specific module or feature. All new tests should be written using the <a title="Unit testing framework for Python." class="reference external" href="unittest.html#module-unittest"><tt class="xref docutils literal"><span class="pre">unittest</span></tt></a> or <a title="Test pieces of code within docstrings." class="reference external" href="doctest.html#module-doctest"><tt class="xref docutils literal"><span class="pre">doctest</span></tt></a> module. Some older tests are written using a “traditional” testing style that compares output printed to <tt class="docutils literal"><span class="pre">sys.stdout</span></tt>; this style of test is considered deprecated.</p> <div class="admonition-see-also admonition seealso"> <p class="first admonition-title">See also</p> <dl class="last docutils"> <dt>Module <a title="Unit testing framework for Python." class="reference external" href="unittest.html#module-unittest"><tt class="xref docutils literal"><span class="pre">unittest</span></tt></a></dt> <dd>Writing PyUnit regression tests.</dd> <dt>Module <a title="Test pieces of code within docstrings." class="reference external" href="doctest.html#module-doctest"><tt class="xref docutils literal"><span class="pre">doctest</span></tt></a></dt> <dd>Tests embedded in documentation strings.</dd> </dl> </div> <div class="section" id="writing-unit-tests-for-the-test-package"> <span id="writing-tests"></span><h2>25.5.1. Writing Unit Tests for the <tt class="xref docutils literal"><span class="pre">test</span></tt> package<a class="headerlink" href="#writing-unit-tests-for-the-test-package" title="Permalink to this headline">¶</a></h2> <p>It is preferred that tests that use the <a title="Unit testing framework for Python." class="reference external" href="unittest.html#module-unittest"><tt class="xref docutils literal"><span class="pre">unittest</span></tt></a> module follow a few guidelines. One is to name the test module by starting it with <tt class="docutils literal"><span class="pre">test_</span></tt> and end it with the name of the module being tested. The test methods in the test module should start with <tt class="docutils literal"><span class="pre">test_</span></tt> and end with a description of what the method is testing. This is needed so that the methods are recognized by the test driver as test methods. Also, no documentation string for the method should be included. A comment (such as <tt class="docutils literal"><span class="pre">#</span> <span class="pre">Tests</span> <span class="pre">function</span> <span class="pre">returns</span> <span class="pre">only</span> <span class="pre">True</span> <span class="pre">or</span> <span class="pre">False</span></tt>) should be used to provide documentation for test methods. This is done because documentation strings get printed out if they exist and thus what test is being run is not stated.</p> <p>A basic boilerplate is often used:</p> <div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">unittest</span> <span class="kn">from</span> <span class="nn">test</span> <span class="kn">import</span> <span class="n">test_support</span> <span class="k">class</span> <span class="nc">MyTestCase1</span><span class="p">(</span><span class="n">unittest</span><span class="o">.</span><span class="n">TestCase</span><span class="p">):</span> <span class="c"># Only use setUp() and tearDown() if necessary</span> <span class="k">def</span> <span class="nf">setUp</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="o">...</span> <span class="n">code</span> <span class="n">to</span> <span class="n">execute</span> <span class="ow">in</span> <span class="n">preparation</span> <span class="k">for</span> <span class="n">tests</span> <span class="o">...</span> <span class="k">def</span> <span class="nf">tearDown</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="o">...</span> <span class="n">code</span> <span class="n">to</span> <span class="n">execute</span> <span class="n">to</span> <span class="n">clean</span> <span class="n">up</span> <span class="n">after</span> <span class="n">tests</span> <span class="o">...</span> <span class="k">def</span> <span class="nf">test_feature_one</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="c"># Test feature one.</span> <span class="o">...</span> <span class="n">testing</span> <span class="n">code</span> <span class="o">...</span> <span class="k">def</span> <span class="nf">test_feature_two</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="c"># Test feature two.</span> <span class="o">...</span> <span class="n">testing</span> <span class="n">code</span> <span class="o">...</span> <span class="o">...</span> <span class="n">more</span> <span class="n">test</span> <span class="n">methods</span> <span class="o">...</span> <span class="k">class</span> <span class="nc">MyTestCase2</span><span class="p">(</span><span class="n">unittest</span><span class="o">.</span><span class="n">TestCase</span><span class="p">):</span> <span class="o">...</span> <span class="n">same</span> <span class="n">structure</span> <span class="k">as</span> <span class="n">MyTestCase1</span> <span class="o">...</span> <span class="o">...</span> <span class="n">more</span> <span class="n">test</span> <span class="n">classes</span> <span class="o">...</span> <span class="k">def</span> <span class="nf">test_main</span><span class="p">():</span> <span class="n">test_support</span><span class="o">.</span><span class="n">run_unittest</span><span class="p">(</span><span class="n">MyTestCase1</span><span class="p">,</span> <span class="n">MyTestCase2</span><span class="p">,</span> <span class="o">...</span> <span class="nb">list</span> <span class="n">other</span> <span class="n">tests</span> <span class="o">...</span> <span class="p">)</span> <span class="k">if</span> <span class="n">__name__</span> <span class="o">==</span> <span class="s">'__main__'</span><span class="p">:</span> <span class="n">test_main</span><span class="p">()</span> </pre></div> </div> <p>This boilerplate code allows the testing suite to be run by <tt class="xref docutils literal"><span class="pre">test.regrtest</span></tt> as well as on its own as a script.</p> <p>The goal for regression testing is to try to break code. This leads to a few guidelines to be followed:</p> <ul> <li><p class="first">The testing suite should exercise all classes, functions, and constants. This includes not just the external API that is to be presented to the outside world but also “private” code.</p> </li> <li><p class="first">Whitebox testing (examining the code being tested when the tests are being written) is preferred. Blackbox testing (testing only the published user interface) is not complete enough to make sure all boundary and edge cases are tested.</p> </li> <li><p class="first">Make sure all possible values are tested including invalid ones. This makes sure that not only all valid values are acceptable but also that improper values are handled correctly.</p> </li> <li><p class="first">Exhaust as many code paths as possible. Test where branching occurs and thus tailor input to make sure as many different paths through the code are taken.</p> </li> <li><p class="first">Add an explicit test for any bugs discovered for the tested code. This will make sure that the error does not crop up again if the code is changed in the future.</p> </li> <li><p class="first">Make sure to clean up after your tests (such as close and remove all temporary files).</p> </li> <li><p class="first">If a test is dependent on a specific condition of the operating system then verify the condition already exists before attempting the test.</p> </li> <li><p class="first">Import as few modules as possible and do it as soon as possible. This minimizes external dependencies of tests and also minimizes possible anomalous behavior from side-effects of importing a module.</p> </li> <li><p class="first">Try to maximize code reuse. On occasion, tests will vary by something as small as what type of input is used. Minimize code duplication by subclassing a basic test class with a class that specifies the input:</p> <div class="highlight-python"><div class="highlight"><pre><span class="k">class</span> <span class="nc">TestFuncAcceptsSequences</span><span class="p">(</span><span class="n">unittest</span><span class="o">.</span><span class="n">TestCase</span><span class="p">):</span> <span class="n">func</span> <span class="o">=</span> <span class="n">mySuperWhammyFunction</span> <span class="k">def</span> <span class="nf">test_func</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">func</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">arg</span><span class="p">)</span> <span class="k">class</span> <span class="nc">AcceptLists</span><span class="p">(</span><span class="n">TestFuncAcceptsSequences</span><span class="p">):</span> <span class="n">arg</span> <span class="o">=</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">]</span> <span class="k">class</span> <span class="nc">AcceptStrings</span><span class="p">(</span><span class="n">TestFuncAcceptsSequences</span><span class="p">):</span> <span class="n">arg</span> <span class="o">=</span> <span class="s">'abc'</span> <span class="k">class</span> <span class="nc">AcceptTuples</span><span class="p">(</span><span class="n">TestFuncAcceptsSequences</span><span class="p">):</span> <span class="n">arg</span> <span class="o">=</span> <span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">)</span> </pre></div> </div> </li> </ul> <div class="admonition-see-also admonition seealso"> <p class="first admonition-title">See also</p> <dl class="last docutils"> <dt>Test Driven Development</dt> <dd>A book by Kent Beck on writing tests before code.</dd> </dl> </div> </div> <div class="section" id="running-tests-using-test-regrtest"> <span id="regrtest"></span><h2>25.5.2. Running tests using <tt class="xref docutils literal"><span class="pre">test.regrtest</span></tt><a class="headerlink" href="#running-tests-using-test-regrtest" title="Permalink to this headline">¶</a></h2> <p><tt class="xref docutils literal"><span class="pre">test.regrtest</span></tt> can be used as a script to drive Python’s regression test suite. Running the script by itself automatically starts running all regression tests in the <tt class="xref docutils literal"><span class="pre">test</span></tt> package. It does this by finding all modules in the package whose name starts with <tt class="docutils literal"><span class="pre">test_</span></tt>, importing them, and executing the function <tt class="xref docutils literal"><span class="pre">test_main()</span></tt> if present. The names of tests to execute may also be passed to the script. Specifying a single regression test (<strong>python regrtest.py</strong> <em class="xref">test_spam.py</em>) will minimize output and only print whether the test passed or failed and thus minimize output.</p> <p>Running <tt class="xref docutils literal"><span class="pre">test.regrtest</span></tt> directly allows what resources are available for tests to use to be set. You do this by using the <a class="reference external" href="../using/cmdline.html#cmdoption-u"><em class="xref">-u</em></a> command-line option. Run <strong>python regrtest.py</strong> <em class="xref">-uall</em> to turn on all resources; specifying <em class="xref">all</em> as an option for <a class="reference external" href="../using/cmdline.html#cmdoption-u"><em class="xref">-u</em></a> enables all possible resources. If all but one resource is desired (a more common case), a comma-separated list of resources that are not desired may be listed after <em class="xref">all</em>. The command <strong>python regrtest.py</strong> <em class="xref">-uall,-audio,-largefile</em> will run <tt class="xref docutils literal"><span class="pre">test.regrtest</span></tt> with all resources except the <em class="xref">audio</em> and <em class="xref">largefile</em> resources. For a list of all resources and more command-line options, run <strong>python regrtest.py</strong> <a class="reference external" href="../using/cmdline.html#cmdoption-h"><em class="xref">-h</em></a>.</p> <p>Some other ways to execute the regression tests depend on what platform the tests are being executed on. On Unix, you can run <strong>make</strong> <em class="xref">test</em> at the top-level directory where Python was built. On Windows, executing <strong>rt.bat</strong> from your <tt class="docutils literal"><span class="pre">PCBuild</span></tt> directory will run all regression tests.</p> </div> </div> <div class="section" id="module-test.test_support"> <h1>25.6. <tt class="xref docutils literal"><span class="pre">test.test_support</span></tt> — Utility functions for tests<a class="headerlink" href="#module-test.test_support" title="Permalink to this headline">¶</a></h1> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">The <tt class="xref docutils literal"><span class="pre">test.test_support</span></tt> module has been renamed to <tt class="xref docutils literal"><span class="pre">test.support</span></tt> in Python 3.x.</p> </div> <p>The <tt class="xref docutils literal"><span class="pre">test.test_support</span></tt> module provides support for Python’s regression tests.</p> <p>This module defines the following exceptions:</p> <dl class="exception"> <dt id="test.test_support.TestFailed"> <em class="property">exception </em><tt class="descclassname">test.test_support.</tt><tt class="descname">TestFailed</tt><a class="headerlink" href="#test.test_support.TestFailed" title="Permalink to this definition">¶</a></dt> <dd>Exception to be raised when a test fails. This is deprecated in favor of <a title="Unit testing framework for Python." class="reference external" href="unittest.html#module-unittest"><tt class="xref docutils literal"><span class="pre">unittest</span></tt></a>-based tests and <a title="unittest.TestCase" class="reference external" href="unittest.html#unittest.TestCase"><tt class="xref docutils literal"><span class="pre">unittest.TestCase</span></tt></a>‘s assertion methods.</dd></dl> <dl class="exception"> <dt id="test.test_support.TestSkipped"> <em class="property">exception </em><tt class="descclassname">test.test_support.</tt><tt class="descname">TestSkipped</tt><a class="headerlink" href="#test.test_support.TestSkipped" title="Permalink to this definition">¶</a></dt> <dd>Subclass of <a title="test.test_support.TestFailed" class="reference internal" href="#test.test_support.TestFailed"><tt class="xref docutils literal"><span class="pre">TestFailed</span></tt></a>. Raised when a test is skipped. This occurs when a needed resource (such as a network connection) is not available at the time of testing.</dd></dl> <dl class="exception"> <dt id="test.test_support.ResourceDenied"> <em class="property">exception </em><tt class="descclassname">test.test_support.</tt><tt class="descname">ResourceDenied</tt><a class="headerlink" href="#test.test_support.ResourceDenied" title="Permalink to this definition">¶</a></dt> <dd>Subclass of <a title="test.test_support.TestSkipped" class="reference internal" href="#test.test_support.TestSkipped"><tt class="xref docutils literal"><span class="pre">TestSkipped</span></tt></a>. Raised when a resource (such as a network connection) is not available. Raised by the <a title="test.test_support.requires" class="reference internal" href="#test.test_support.requires"><tt class="xref docutils literal"><span class="pre">requires()</span></tt></a> function.</dd></dl> <p>The <tt class="xref docutils literal"><span class="pre">test.test_support</span></tt> module defines the following constants:</p> <dl class="data"> <dt id="test.test_support.verbose"> <tt class="descclassname">test.test_support.</tt><tt class="descname">verbose</tt><a class="headerlink" href="#test.test_support.verbose" title="Permalink to this definition">¶</a></dt> <dd><a title="True" class="reference external" href="constants.html#True"><tt class="xref xref docutils literal"><span class="pre">True</span></tt></a> when verbose output is enabled. Should be checked when more detailed information is desired about a running test. <em>verbose</em> is set by <tt class="xref docutils literal"><span class="pre">test.regrtest</span></tt>.</dd></dl> <dl class="data"> <dt id="test.test_support.have_unicode"> <tt class="descclassname">test.test_support.</tt><tt class="descname">have_unicode</tt><a class="headerlink" href="#test.test_support.have_unicode" title="Permalink to this definition">¶</a></dt> <dd><a title="True" class="reference external" href="constants.html#True"><tt class="xref xref docutils literal"><span class="pre">True</span></tt></a> when Unicode support is available.</dd></dl> <dl class="data"> <dt id="test.test_support.is_jython"> <tt class="descclassname">test.test_support.</tt><tt class="descname">is_jython</tt><a class="headerlink" href="#test.test_support.is_jython" title="Permalink to this definition">¶</a></dt> <dd><a title="True" class="reference external" href="constants.html#True"><tt class="xref xref docutils literal"><span class="pre">True</span></tt></a> if the running interpreter is Jython.</dd></dl> <dl class="data"> <dt id="test.test_support.TESTFN"> <tt class="descclassname">test.test_support.</tt><tt class="descname">TESTFN</tt><a class="headerlink" href="#test.test_support.TESTFN" title="Permalink to this definition">¶</a></dt> <dd>Set to the path that a temporary file may be created at. Any temporary that is created should be closed and unlinked (removed).</dd></dl> <p>The <tt class="xref docutils literal"><span class="pre">test.test_support</span></tt> module defines the following functions:</p> <dl class="function"> <dt id="test.test_support.forget"> <tt class="descclassname">test.test_support.</tt><tt class="descname">forget</tt><big>(</big><em>module_name</em><big>)</big><a class="headerlink" href="#test.test_support.forget" title="Permalink to this definition">¶</a></dt> <dd>Removes the module named <em>module_name</em> from <tt class="docutils literal"><span class="pre">sys.modules</span></tt> and deletes any byte-compiled files of the module.</dd></dl> <dl class="function"> <dt id="test.test_support.is_resource_enabled"> <tt class="descclassname">test.test_support.</tt><tt class="descname">is_resource_enabled</tt><big>(</big><em>resource</em><big>)</big><a class="headerlink" href="#test.test_support.is_resource_enabled" title="Permalink to this definition">¶</a></dt> <dd>Returns <a title="True" class="reference external" href="constants.html#True"><tt class="xref xref docutils literal"><span class="pre">True</span></tt></a> if <em>resource</em> is enabled and available. The list of available resources is only set when <tt class="xref docutils literal"><span class="pre">test.regrtest</span></tt> is executing the tests.</dd></dl> <dl class="function"> <dt id="test.test_support.requires"> <tt class="descclassname">test.test_support.</tt><tt class="descname">requires</tt><big>(</big><em>resource</em><span class="optional">[</span>, <em>msg</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#test.test_support.requires" title="Permalink to this definition">¶</a></dt> <dd>Raises <a title="test.test_support.ResourceDenied" class="reference internal" href="#test.test_support.ResourceDenied"><tt class="xref docutils literal"><span class="pre">ResourceDenied</span></tt></a> if <em>resource</em> is not available. <em>msg</em> is the argument to <a title="test.test_support.ResourceDenied" class="reference internal" href="#test.test_support.ResourceDenied"><tt class="xref docutils literal"><span class="pre">ResourceDenied</span></tt></a> if it is raised. Always returns true if called by a function whose <tt class="docutils literal"><span class="pre">__name__</span></tt> is <tt class="docutils literal"><span class="pre">'__main__'</span></tt>. Used when tests are executed by <tt class="xref docutils literal"><span class="pre">test.regrtest</span></tt>.</dd></dl> <dl class="function"> <dt id="test.test_support.findfile"> <tt class="descclassname">test.test_support.</tt><tt class="descname">findfile</tt><big>(</big><em>filename</em><big>)</big><a class="headerlink" href="#test.test_support.findfile" title="Permalink to this definition">¶</a></dt> <dd>Return the path to the file named <em>filename</em>. If no match is found <em>filename</em> is returned. This does not equal a failure since it could be the path to the file.</dd></dl> <dl class="function"> <dt id="test.test_support.run_unittest"> <tt class="descclassname">test.test_support.</tt><tt class="descname">run_unittest</tt><big>(</big><em>*classes</em><big>)</big><a class="headerlink" href="#test.test_support.run_unittest" title="Permalink to this definition">¶</a></dt> <dd><p>Execute <a title="unittest.TestCase" class="reference external" href="unittest.html#unittest.TestCase"><tt class="xref docutils literal"><span class="pre">unittest.TestCase</span></tt></a> subclasses passed to the function. The function scans the classes for methods starting with the prefix <tt class="docutils literal"><span class="pre">test_</span></tt> and executes the tests individually.</p> <p>It is also legal to pass strings as parameters; these should be keys in <tt class="docutils literal"><span class="pre">sys.modules</span></tt>. Each associated module will be scanned by <tt class="docutils literal"><span class="pre">unittest.TestLoader.loadTestsFromModule()</span></tt>. This is usually seen in the following <tt class="xref docutils literal"><span class="pre">test_main()</span></tt> function:</p> <div class="highlight-python"><div class="highlight"><pre><span class="k">def</span> <span class="nf">test_main</span><span class="p">():</span> <span class="n">test_support</span><span class="o">.</span><span class="n">run_unittest</span><span class="p">(</span><span class="n">__name__</span><span class="p">)</span> </pre></div> </div> <p>This will run all tests defined in the named module.</p> </dd></dl> <dl class="function"> <dt id="test.test_support.check_warnings"> <tt class="descclassname">test.test_support.</tt><tt class="descname">check_warnings</tt><big>(</big><big>)</big><a class="headerlink" href="#test.test_support.check_warnings" title="Permalink to this definition">¶</a></dt> <dd><p>A convenience wrapper for <tt class="docutils literal"><span class="pre">warnings.catch_warnings()</span></tt> that makes it easier to test that a warning was correctly raised with a single assertion. It is approximately equivalent to calling <tt class="docutils literal"><span class="pre">warnings.catch_warnings(record=True)</span></tt>.</p> <p>The main difference is that on entry to the context manager, a <tt class="xref docutils literal"><span class="pre">WarningRecorder</span></tt> instance is returned instead of a simple list. The underlying warnings list is available via the recorder object’s <tt class="xref docutils literal"><span class="pre">warnings</span></tt> attribute, while the attributes of the last raised warning are also accessible directly on the object. If no warning has been raised, then the latter attributes will all be <a title="None" class="reference external" href="constants.html#None"><tt class="xref xref docutils literal"><span class="pre">None</span></tt></a>.</p> <p>A <tt class="xref docutils literal"><span class="pre">reset()</span></tt> method is also provided on the recorder object. This method simply clears the warning list.</p> <p>The context manager is used like this:</p> <div class="highlight-python"><div class="highlight"><pre><span class="k">with</span> <span class="n">check_warnings</span><span class="p">()</span> <span class="k">as</span> <span class="n">w</span><span class="p">:</span> <span class="n">warnings</span><span class="o">.</span><span class="n">simplefilter</span><span class="p">(</span><span class="s">"always"</span><span class="p">)</span> <span class="n">warnings</span><span class="o">.</span><span class="n">warn</span><span class="p">(</span><span class="s">"foo"</span><span class="p">)</span> <span class="k">assert</span> <span class="nb">str</span><span class="p">(</span><span class="n">w</span><span class="o">.</span><span class="n">message</span><span class="p">)</span> <span class="o">==</span> <span class="s">"foo"</span> <span class="n">warnings</span><span class="o">.</span><span class="n">warn</span><span class="p">(</span><span class="s">"bar"</span><span class="p">)</span> <span class="k">assert</span> <span class="nb">str</span><span class="p">(</span><span class="n">w</span><span class="o">.</span><span class="n">message</span><span class="p">)</span> <span class="o">==</span> <span class="s">"bar"</span> <span class="k">assert</span> <span class="nb">str</span><span class="p">(</span><span class="n">w</span><span class="o">.</span><span class="n">warnings</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">message</span><span class="p">)</span> <span class="o">==</span> <span class="s">"foo"</span> <span class="k">assert</span> <span class="nb">str</span><span class="p">(</span><span class="n">w</span><span class="o">.</span><span class="n">warnings</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span><span class="o">.</span><span class="n">message</span><span class="p">)</span> <span class="o">==</span> <span class="s">"bar"</span> <span class="n">w</span><span class="o">.</span><span class="n">reset</span><span class="p">()</span> <span class="k">assert</span> <span class="nb">len</span><span class="p">(</span><span class="n">w</span><span class="o">.</span><span class="n">warnings</span><span class="p">)</span> <span class="o">==</span> <span class="mi">0</span> </pre></div> </div> <p class="versionadded"> <span class="versionmodified">New in version 2.6.</span></p> </dd></dl> <dl class="function"> <dt id="test.test_support.captured_stdout"> <tt class="descclassname">test.test_support.</tt><tt class="descname">captured_stdout</tt><big>(</big><big>)</big><a class="headerlink" href="#test.test_support.captured_stdout" title="Permalink to this definition">¶</a></dt> <dd><p>This is a context manager that runs the <a class="reference external" href="../reference/compound_stmts.html#with"><tt class="xref docutils literal"><span class="pre">with</span></tt></a> statement body using a <a title="StringIO.StringIO" class="reference external" href="stringio.html#StringIO.StringIO"><tt class="xref docutils literal"><span class="pre">StringIO.StringIO</span></tt></a> object as sys.stdout. That object can be retrieved using the <tt class="docutils literal"><span class="pre">as</span></tt> clause of the <a class="reference external" href="../reference/compound_stmts.html#with"><tt class="xref docutils literal"><span class="pre">with</span></tt></a> statement.</p> <p>Example use:</p> <div class="highlight-python"><div class="highlight"><pre><span class="k">with</span> <span class="n">captured_stdout</span><span class="p">()</span> <span class="k">as</span> <span class="n">s</span><span class="p">:</span> <span class="k">print</span> <span class="s">"hello"</span> <span class="k">assert</span> <span class="n">s</span><span class="o">.</span><span class="n">getvalue</span><span class="p">()</span> <span class="o">==</span> <span class="s">"hello"</span> </pre></div> </div> <p class="versionadded"> <span class="versionmodified">New in version 2.6.</span></p> </dd></dl> <p>The <tt class="xref docutils literal"><span class="pre">test.test_support</span></tt> module defines the following classes:</p> <dl class="class"> <dt id="test.test_support.TransientResource"> <em class="property">class </em><tt class="descclassname">test.test_support.</tt><tt class="descname">TransientResource</tt><big>(</big><em>exc</em><span class="optional">[</span>, <em>**kwargs</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#test.test_support.TransientResource" title="Permalink to this definition">¶</a></dt> <dd><p>Instances are a context manager that raises <a title="test.test_support.ResourceDenied" class="reference internal" href="#test.test_support.ResourceDenied"><tt class="xref docutils literal"><span class="pre">ResourceDenied</span></tt></a> if the specified exception type is raised. Any keyword arguments are treated as attribute/value pairs to be compared against any exception raised within the <a class="reference external" href="../reference/compound_stmts.html#with"><tt class="xref docutils literal"><span class="pre">with</span></tt></a> statement. Only if all pairs match properly against attributes on the exception is <a title="test.test_support.ResourceDenied" class="reference internal" href="#test.test_support.ResourceDenied"><tt class="xref docutils literal"><span class="pre">ResourceDenied</span></tt></a> raised.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.6.</span></p> </dd></dl> <dl class="class"> <dt id="test.test_support.EnvironmentVarGuard"> <em class="property">class </em><tt class="descclassname">test.test_support.</tt><tt class="descname">EnvironmentVarGuard</tt><a class="headerlink" href="#test.test_support.EnvironmentVarGuard" title="Permalink to this definition">¶</a></dt> <dd><p>Class used to temporarily set or unset environment variables. Instances can be used as a context manager.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.6.</span></p> </dd></dl> <dl class="method"> <dt id="test.test_support.EnvironmentVarGuard.set"> <tt class="descclassname">EnvironmentVarGuard.</tt><tt class="descname">set</tt><big>(</big><em>envvar</em>, <em>value</em><big>)</big><a class="headerlink" href="#test.test_support.EnvironmentVarGuard.set" title="Permalink to this definition">¶</a></dt> <dd>Temporarily set the environment variable <tt class="docutils literal"><span class="pre">envvar</span></tt> to the value of <tt class="docutils literal"><span class="pre">value</span></tt>.</dd></dl> <dl class="method"> <dt id="test.test_support.EnvironmentVarGuard.unset"> <tt class="descclassname">EnvironmentVarGuard.</tt><tt class="descname">unset</tt><big>(</big><em>envvar</em><big>)</big><a class="headerlink" href="#test.test_support.EnvironmentVarGuard.unset" title="Permalink to this definition">¶</a></dt> <dd>Temporarily unset the environment variable <tt class="docutils literal"><span class="pre">envvar</span></tt>.</dd></dl> <dl class="class"> <dt id="test.test_support.WarningsRecorder"> <em class="property">class </em><tt class="descclassname">test.test_support.</tt><tt class="descname">WarningsRecorder</tt><a class="headerlink" href="#test.test_support.WarningsRecorder" title="Permalink to this definition">¶</a></dt> <dd><p>Class used to record warnings for unit tests. See documentation of <a title="test.test_support.check_warnings" class="reference internal" href="#test.test_support.check_warnings"><tt class="xref docutils literal"><span class="pre">check_warnings()</span></tt></a> above for more details.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.6.</span></p> </dd></dl> </div> </div> </div> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"> <h3><a href="../contents.html">Table Of Contents</a></h3> <ul> <li><a class="reference external" href="#">25.5. <tt class="docutils literal"><span class="pre">test</span></tt> — Regression tests package for Python</a><ul> <li><a class="reference external" href="#writing-unit-tests-for-the-test-package">25.5.1. Writing Unit Tests for the <tt class="docutils literal"><span class="pre">test</span></tt> package</a></li> <li><a class="reference external" href="#running-tests-using-test-regrtest">25.5.2. Running tests using <tt class="docutils literal"><span class="pre">test.regrtest</span></tt></a></li> </ul> </li> <li><a class="reference external" href="#module-test.test_support">25.6. <tt class="docutils literal"><span class="pre">test.test_support</span></tt> — Utility functions for tests</a></li> </ul> <h4>Previous topic</h4> <p class="topless"><a href="2to3.html" title="previous chapter">25.4. 2to3 - Automated Python 2 to 3 code translation</a></p> <h4>Next topic</h4> <p class="topless"><a href="debug.html" title="next chapter">26. Debugging and Profiling</a></p> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li><a href="../_sources/library/test.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" size="18" /> <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="../modindex.html" title="Global Module Index" >modules</a> |</li> <li class="right" > <a href="debug.html" title="26. Debugging and Profiling" >next</a> |</li> <li class="right" > <a href="2to3.html" title="25.4. 2to3 - Automated Python 2 to 3 code translation" >previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="../index.html">Python v2.6.6 documentation</a> »</li> <li><a href="index.html" >The Python Standard Library</a> »</li> <li><a href="development.html" >25. Development Tools</a> »</li> </ul> </div> <div class="footer"> © <a href="../copyright.html">Copyright</a> 1990-2011, Python Software Foundation. <br /> The Python Software Foundation is a non-profit corporation. <a href="http://www.python.org/psf/donations/">Please donate.</a> <br /> Last updated on Jul 20, 2011. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 0.6.6. </div> </body> </html>
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