<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <!-- qttestlib-manual.qdoc --> <title>Chapter 1: Writing a Unit Test | Qt Test 5.12.6</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td >Qt 5.12</td><td ><a href="qttest-index.html">Qt Test</a></td><td >Chapter 1: Writing a Unit Test</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qttest-index.html">Qt 5.12.6 Reference Documentation</a></td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <link rel="next" href="qttestlib-tutorial2-example.html" /> <p class="naviNextPrevious headerNavi"> <a class="nextPage" href="qttestlib-tutorial2-example.html">Chapter 2</a> </p><p/> <div class="sidebar"> <div class="toc"> <h3><a name="toc">Contents</a></h3> <ul> <li class="level1"><a href="#writing-a-test">Writing a Test</a></li> <li class="level1"><a href="#executing-a-test">Executing a Test</a></li> </ul> </div> <div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">Chapter 1: Writing a Unit Test</h1> <span class="subtitle"></span> <!-- $$$tutorial1-brief --> <p>How to write a unit test.</p> <!-- @@@tutorial1 --> <!-- $$$tutorial1-description --> <div class="descr"> <a name="details"></a> <p>In this first chapter we will see how to write a simple unit test for a class, and how to execute it.</p> <a name="writing-a-test"></a> <h2 id="writing-a-test">Writing a Test</h2> <p>Let's assume you want to test the behavior of our <a href="../qtcore/qstring.html">QString</a> class. First, you need a class that contains your test functions. This class has to inherit from <a href="../qtcore/qobject.html">QObject</a>:</p> <pre class="cpp"> <span class="preprocessor">#include <QtTest/QtTest></span> <span class="keyword">class</span> TestQString: <span class="keyword">public</span> <span class="type"><a href="../qtcore/qobject.html">QObject</a></span> { Q_OBJECT <span class="keyword">private</span> <span class="keyword">slots</span>: <span class="type">void</span> toUpper(); }; </pre> <p><b>Note: </b>You need to include the <a href="qtest.html">QTest</a> header and declare the test functions as private slots so the test framework finds and executes it.</p><p>Then you need to implement the test function itself. The implementation could look like this:</p> <pre class="cpp"> <span class="type">void</span> TestQString<span class="operator">::</span>toUpper() { <span class="type"><a href="../qtcore/qstring.html">QString</a></span> str <span class="operator">=</span> <span class="string">"Hello"</span>; QVERIFY(str<span class="operator">.</span>toUpper() <span class="operator">=</span><span class="operator">=</span> <span class="string">"HELLO"</span>); } </pre> <p>The <a href="qtest.html#QVERIFY">QVERIFY</a>() macro evaluates the expression passed as its argument. If the expression evaluates to true, the execution of the test function continues. Otherwise, a message describing the failure is appended to the test log, and the test function stops executing.</p> <p>But if you want a more verbose output to the test log, you should use the <a href="qtest.html#QCOMPARE">QCOMPARE</a>() macro instead:</p> <pre class="cpp"> <span class="type">void</span> TestQString<span class="operator">::</span>toUpper() { <span class="type"><a href="../qtcore/qstring.html">QString</a></span> str <span class="operator">=</span> <span class="string">"Hello"</span>; QCOMPARE(str<span class="operator">.</span>toUpper()<span class="operator">,</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span>(<span class="string">"HELLO"</span>)); } </pre> <p>If the strings are not equal, the contents of both strings are appended to the test log, making it immediately visible why the comparison failed.</p> <p>Finally, to make our test case a stand-alone executable, the following two lines are needed:</p> <pre class="cpp"> QTEST_MAIN(TestQString) <span class="preprocessor">#include "testqstring.moc"</span> </pre> <p>The <a href="qtest.html#QTEST_MAIN">QTEST_MAIN</a>() macro expands to a simple <code>main()</code> method that runs all the test functions. Note that if both the declaration and the implementation of our test class are in a <code>.cpp</code> file, we also need to include the generated moc file to make Qt's introspection work.</p> <a name="executing-a-test"></a> <h2 id="executing-a-test">Executing a Test</h2> <p>Now that we finished writing our test, we want to execute it. Assuming that our test was saved as <code>testqstring.cpp</code> in an empty directory, we build the test using qmake to create a project and generate a makefile.</p> <pre class="cpp"> <span class="operator">/</span>myTestDirectory$ qmake <span class="operator">-</span>project <span class="string">"QT += testlib"</span> <span class="operator">/</span>myTestDirectory$ qmake <span class="operator">/</span>myTestDirectory$ make </pre> <p><b>Note: </b>If you're using windows, replace <code>make</code> with <code>nmake</code> or whatever build tool you use.</p><p>Running the resulting executable should give you the following output:</p> <pre class="cpp"> <span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span> Start testing of TestQString <span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span> Config: Using <span class="type"><a href="qttest-module.html">QtTest</a></span> library <span class="operator">%</span>VERSION<span class="operator">%</span><span class="operator">,</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span> <span class="operator">%</span>VERSION<span class="operator">%</span> PASS : TestQString<span class="operator">::</span>initTestCase() PASS : TestQString<span class="operator">::</span>toUpper() PASS : TestQString<span class="operator">::</span>cleanupTestCase() Totals: <span class="number">3</span> passed<span class="operator">,</span> <span class="number">0</span> failed<span class="operator">,</span> <span class="number">0</span> skipped <span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span> Finished testing of TestQString <span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span><span class="operator">*</span> </pre> <p>Congratulations! You just wrote and executed your first unit test using the Qt Test framework.</p> <p>Files:</p> <ul> <li><a href="qttestlib-tutorial1-testqstring-cpp.html">tutorial1/testqstring.cpp</a></li> <li><a href="qttestlib-tutorial1-tutorial1-pro.html">tutorial1/tutorial1.pro</a></li> </ul> </div> <!-- @@@tutorial1 --> <p class="naviNextPrevious footerNavi"> <a class="nextPage" href="qttestlib-tutorial2-example.html">Chapter 2</a> </p> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2019 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.<br/> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br/> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners. </p> </div> </body> </html>