# Tutorial

`pytest-qt` registers a new fixture named `qtbot`, which acts as bot in the sense that it can send keyboard and mouse events to any widgets being tested. This way, the programmer can simulate user interaction while checking if GUI controls are behaving in the expected manner.

To illustrate that, consider a widget constructed to allow the user to find files in a given directory inside an application.

It is a very simple dialog, where the user enters a standard file mask, optionally enters file text to search for and a button to browse for the desired directory. Its source code is available here,

To test this widget’s basic functionality, create a test function:

    def test_basic_search(qtbot, tmpdir):
        '''
        test to ensure basic find files functionality is working.
        '''
        tmpdir.join('video1.avi').ensure()
        tmpdir.join('video1.srt').ensure()

        tmpdir.join('video2.avi').ensure()
        tmpdir.join('video2.srt').ensure()

Here the first parameter indicates that we will be using a `qtbot` fixture to control our widget. The other parameter is pytest’s standard tmpdir that we use to create some files that will be used during our test.

Now we create the widget to test and register it:

    window = Window()
    window.show()
    qtbot.addWidget(window)

Tip

Registering widgets is not required, but recommended because it will ensure those widgets get properly closed after each test is done.

Now we use `qtbot` methods to simulate user interaction with the dialog:

    window.fileComboBox.clear()
    qtbot.keyClicks(window.fileComboBox, '*.avi')

    window.directoryComboBox.clear()
    qtbot.keyClicks(window.directoryComboBox, str(tmpdir))

The method `keyClicks` is used to enter text in the editable combo box, selecting the desired mask and directory.

We then simulate a user clicking the button with the `mouseClick` method:

    qtbot.mouseClick(window.findButton, QtCore.Qt.LeftButton)

Once this is done, we inspect the results widget to ensure that it contains the expected files we created earlier:

    assert window.filesTable.rowCount() == 2
    assert window.filesTable.item(0, 0).text() == 'video1.avi'
    assert window.filesTable.item(1, 0).text() == 'video2.avi'