Chapter 3: Simulating GUI Events

Files:

QTestLib features some mechanisms to test graphical user interfaces. Instead of simulating native window system events, QTestLib sends internal Qt events. That means there are no side-effects on the machine the tests are running on.

In this chapter we will se how to write a simple GUI test.

Writing a GUI test

This time, let's assume you want to test the behavior of our QLineEdit class. As before, you will need a class that contains your test function:

 #include <QtGui>
 #include <QtTest/QtTest>

 class TestGui: public QObject
 {
     Q_OBJECT

 private slots:
     void testGui();

 };

The only difference is that you need to include the QtGui class definitions in addition to the QTest namespace.

 void TestGui::testGui()
 {
     QLineEdit lineEdit;

     QTest::keyClicks(&lineEdit, "hello world");

     QCOMPARE(lineEdit.text(), QString("hello world"));
 }

In the implementation of the test function we first create a QLineEdit. Then we simulate writing "hello world" in the line edit using the QTest::keyClicks() function.

Note: The widget must also be shown in order to correctly test keyboard shortcuts.

QTest::keyClicks() simulates clicking a sequence of keys on a widget. Optionally, a keyboard modifier can be specified as well as a delay (in milliseconds) of the test after each key click. In a similar way, you can use the QTest::keyClick(), QTest::keyPress(), QTest::keyRelease(), QTest::mouseClick(), QTest::mouseDClick(), QTest::mouseMove(), QTest::mousePress() and QTest::mouseRelease() functions to simulate the associated GUI events.

Finally, we use the QCOMPARE() macro to check if the line edit's text is as expected.

As before, to make our test case a stand-alone executable, the following two lines are needed:

 QTEST_MAIN(TestGui)
 #include "testgui.moc"

The QTEST_MAIN() macro expands to a simple main() method that runs all the test functions, and since both the declaration and the implementation of our test class are in a .cpp file, we also need to include the generated moc file to make Qt's introspection work.

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