/home/rafl

Lots of CPAN distributions require some kind of graphical environment. Some of them even pop up windows, which not only very annoying, but also sometimes fails if you're using a tiled window manager.

To test such distributions on a machine where no graphical environment is available or on your desktop while you're working and don't want to get annoyed to death you can use a fake X server, like Xvfb.

The easiest way to do that is to run

$ xvfb-run -a make test

instead of a plain make test. That'll automatically create a fake xserver, set up DISPLAY and run make test in that environment.

That works well for manually installing modules. When installing using CPAN.pm you can make things easier by writing a distropref.

First, tell cpan where your distroprefs are. I use ~/.cpan/prefs:

$ cpan
cpan[1]> o conf init prefs_dir
[...]
<prefs_dir>
Directory where to store default options/environment/dialogs for
building modules that need some customization? [] /home/rafl/.cpan/prefs
cpan[3]> o conf commit
commit: wrote '/home/rafl/.cpan/CPAN/MyConfig.pm'

Now write a distropref for the modules that need an X server and put it into your prefs dir as X11.yml

---
match:
  distribution: |
    /(?x:Wx
      |Gtk2
      |Gnome2
      |... other modules requiring an X server
    )-\d|
test:
  commandline: "xvfb-run -a make test"

Now the tests for Wx, Gtk2, Gnome2 and all other distributions you list in that regex will be executed with a fake X server.

I have yet to figure out how to write a distropref that just prepends to the test commandline instead of replacing it so I won't need to have another pref for all modules using Module::Build.