Test-Driving X11 GUIs
by George Nistorica
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Pages: 1, 2, 3
Sending Mouse Events to an Application
Sending keys may be not enough in some situations. Having an application that has keyboard shortcuts is nice, but not all of them support it. Sometimes you may need to send mouse events.
To get the absolute position of the appropriate window on your desktop:
my ($x, $y, $width, $height) = GetWindowPos($edit_windows[0]);Suppose that you want to click right in the middle of it. First, compute the position of the middle of the window:
$x += $width / 2;
$y += $height / 2;Now move the mouse:
MoveMouseAbs( $x, $y );Then press the right mouse button:
PressMouseButton M_RIGHT;Do something useful, and then release the mouse button. (Don't forget to do that when you're using PressMouseButton; otherwise, you may experience "strange" desktop behavior when your testing application exits.)
ReleaseMouseButton M_RIGHTYou could replace PressMouseButton() and ReleaseMouseButton() with ClickMouseButton() if you don't have anything to do between pressing and releasing the mouse button.
In the example programs, there's something to do--navigating the context menu with keystrokes.
Moving a Window
This is a neat and interesting feature: the ability to move windows. While it is useful to impress your friends with having their favorite mail program moving up and down, its utility lies in the fact that you can arrange the tested windows on the desktop so they are all visible.
MoveWindow( $window_id, $x, $y );Limitations
As you may have noticed reading the example code, there is almost no way of validating the fact that you are indeed interacting with the right widget or window. The functions you can use for this are FindWindow* or WaitWindow*, which return a list of windows whose titles match an arbitrary regexp, and the functions that deal with child windows, such as IsChild() and GetChildWindows().
While you may pass the window ID to a testing program, using external means to validate the tested application (such as indicating the coordinates on the screen), the problem is that you can't grab a widget's contents.
Also, while you might be tempted to parse the child tree of an application to get from the main window to one of its children, this doesn't work every time. Plenty of GUIs spawn other windows at the top level, and the spawned windows have as root window the topmost window (which is the desktop).
Here's an example of the problem that uses Mozilla Firefox. Before running the test, you must meet some prerequisites:
- Back up your preferences before running the tests.
- Go to Edit -> Preferences -> General -> Connection Settings and set it to "Direct connection to the Internet."
- Click OK, and then OK, and close the browser.
Now run the Firefox.pl example code.
The test program assumes that when the Preferences window pops up, the General menu is selected.
Open Mozilla Firefox again, go to Preferences, select the Web Features menu, click OK, and exit the browser.
Rerun the Firefox.pl program, and watch it.
It has no idea which menu is selected, because every menu component belongs to the same window, having the same title.
