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<table border="0" cellspacing="0" cellpadding="3" width="100%"><tr><td> <div align="center" id="bldcontent"> <a href="../default.htm"><img src="../images/opendocs.png" width="63" height="76" border="0"></a> <br> <div class="symbol">Your OpenSource Publisher™</div> </div> </td></tr></table> <div align="center" class="author"> <a href="../products.lxp">Products</a> | <a href="../wheretobuy.lxp">Where to buy</a> | <a href="../bookstore.lxp">Retailers</a> | <a href="../faq.lxp">FAQ</a> | <a href="../writeforus.lxp">Write for Us.</a> | <a href="#contact">Contact Us.</a> </div> <table border="0" cellspacing="3" cellpadding="0" width="100%"><tr><td width="100%"> <div class="content"> <table border="0" cellspacing="2" cellpadding="0" width="100%"><tr><td width="100%"> <div align="center"><H4 CLASS="AUTHOR"><A NAME="AEN5">Boudewijn Rempt</A><br><a href="../../https@secure.linuxports.com/opendocs/default.htm"><img src=odpyqt125.png></a><br>ISBN: 0-97003300-4-4<br><a href="../../https@secure.linuxports.com/opendocs/default.htm">Available from bookstores everywhere or you can order it here.</a><p>You can download the source files for the book <a href="pyqtsrc.tgz">(code / eps) here.</a><hr></div> <HTML><HEAD><TITLE>A more complicated test</TITLE><METANAME="GENERATOR"CONTENT="Modular DocBook HTML Stylesheet Version 1.72"><LINKREL="HOME"TITLE="GUI Programming with Python: QT Edition"HREF="book1.htm"><LINKREL="UP"TITLE="Automatic testing with PyUnit"HREF="c5064.htm"><LINKREL="PREVIOUS"TITLE="Collecting tests in a test suite"HREF="x5171.htm"><LINKREL="NEXT"TITLE="Large projects"HREF="x5234.htm"></HEAD><BODYCLASS="SECT1"BGCOLOR="#FFFFFF"TEXT="#000000"LINK="#0000FF"VLINK="#840084"ALINK="#0000FF"><DIVCLASS="NAVHEADER"><TABLESUMMARY="Header navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><THCOLSPAN="3"ALIGN="center">GUI Programming with Python: QT Edition</TH></TR><TR><TDWIDTH="10%"ALIGN="left"VALIGN="bottom"><A accesskey="P" href="index.lxp@lxpwrap=x5171_252ehtm.htm">Prev</A></TD><TDWIDTH="80%"ALIGN="center"VALIGN="bottom">Chapter 14. Automatic testing with PyUnit</TD><TDWIDTH="10%"ALIGN="right"VALIGN="bottom"><A accesskey="N" href="index.lxp@lxpwrap=x5234_252ehtm.htm">Next</A></TD></TR></TABLE><HRALIGN="LEFT"WIDTH="100%"></DIV><DIVCLASS="SECT1"><H1CLASS="SECT1">A more complicated test</A></H1><P>Remember, we have two tests to perform on the <TTCLASS="CLASSNAME">DocviewDoc</TT> class. It would be a bit messy and chaotic to write separate testcase classes for those two tests. Additionally, in many cases you will have to prepare an environment for those tests, and it would be a pity to duplicate that code across many test classes.</P><P>It is therefore possible to create more than one testing method for each testcase. For each test method a separate instance of the test object is created and added to the test suite. These methods customarily start with ‘check', but that's not necessary.</P><PRECLASS="PROGRAMLISTING">## dvt2.py - a simple test of instantiating a document#import sysimport unittestfrom docviewdoc import DocviewDocclass DocviewDocTestCase(unittest.TestCase): """DocviewDocTestCase test the DocviewDoc class. """ def checkInstantion(self): """Check whether the document could be instantiated""" doc=None doc=DocviewDoc() except: self.fail("Could not instantiate document for reason: " + sys.exc_info()[0]) else: assert doc!=None, 'Could not instantiate DocviewDoc' def checkModifiable(self): """Check whether the document could be modified""" doc=DocviewDoc() doc.slotModify() assert doc.isModified(), 'Document could not be modified' def checkUniverse(self): """Check whether the universe is still sane""" try: val = 1 / 0 except ZeroDivisionError: pass # all natural laws still hold else: fail ("The universe has been demolished and replaced with chaos.")def suite(): testSuite=unittest.TestSuite() testSuite.addTest(DocviewDocTestCase("checkInstantion")) testSuite.addTest(DocviewDocTestCase("checkModifiable")) return testSuitedef main(): runner = unittest.TextTestRunner() runner.run(suite())if __name__=="__main__": main() </PRE><P>In this case, <TTCLASS="CLASSNAME">DocviewDocTestCase</TT> contains two tests: <TTCLASS="FUNCTION">checkInstantion</TT> and <TTCLASS="FUNCTION">checkModifiable</TT>. This means that two instances of <TTCLASS="CLASSNAME">DocviewDocTestCase</TT> are added to the testsuite.</P><P>I've also added a small test of the universe, to show how to test that your exceptions are fired when you feed your classes illegal input. There are many cases in which you want your code to raise an exception, rather than silently continuing to churn out illegal data. In those cases, you will want the test to succeed when the exception is raised. On the other hand, if the exception is not raised, something happens, and the test fails. That's exactly what the try...except...else block in <TTCLASS="FUNCTION">testUniverse</TT> does.</P><P>You can thus use the <TTCLASS="FUNCTION">fail()</TT> function to let a test noisily fail with a message. There are two similar functions: <TTCLASS="FUNCTION">failIf()</TT> and <TTCLASS="FUNCTION">failUnless()</TT>, that cause the test to fail if the tested expression is true and if the tested expression is false, respectively:</P><PRECLASS="PROGRAMLISTING"> def checkFailUnless(self): self.failUnless(1==1, "One should be one.") def checkFailIf(self): self.failIf(1==2,"I don't one to be one, I want it to be two.") </PRE><P>A shorter way to check that an exception is indeed raised, is to use <TTCLASS="FUNCTION">assertRaises</TT>: </P><PRECLASS="PROGRAMLISTING">def divide(a, b): return a/b...def checkShortCircuitException(self): self.assertRaises(ZeroDivisionError, divide, 1, 0) </PRE><P>The first argument is the exception that should be raised. The second argument of <TTCLASS="FUNCTION">assertRaises()</TT> must be a callable object, such as a function. The other arguments are simply the arguments that should be passed to the function.</P></DIV><DIVCLASS="NAVFOOTER"><HRALIGN="LEFT"WIDTH="100%"><TABLESUMMARY="Footer navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top"><A accesskey="P" href="index.lxp@lxpwrap=x5171_252ehtm.htm">Prev</A></TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><A accesskey="H" href="index.lxp@lxpwrap=book1_252ehtm">Home</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top"><A accesskey="N" href="index.lxp@lxpwrap=x5234_252ehtm.htm">Next</A></TD></TR><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top">Collecting tests in a test suite</TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><A accesskey="U" href="index.lxp@lxpwrap=c5064_252ehtm.htm">Up</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top">Large projects</TD></TR></TABLE></DIV></BODY></HTML> </td> </tr> </table> </td> </tr> </table> ⌨️ 快捷键说明
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