[gimp] app/tests: Give possible solution to 'keyboard_zoom_focus' failing

[Martin Nordholts <martinn src gnome org>]

commit 9e6f5000a588f31f22e2e5cf6c97a753012bd826
Author: Martin Nordholts <martinn src gnome org>
Date:   Mon Oct 25 13:58:09 2010 +0200

    app/tests: Give possible solution to 'keyboard_zoom_focus' failing

 app/tests/test-ui.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)
---
diff --git a/app/tests/test-ui.c b/app/tests/test-ui.c
index e2d8def..b6d115e 100644
--- a/app/tests/test-ui.c
+++ b/app/tests/test-ui.c
@@ -338,7 +338,15 @@ keyboard_zoom_focus (GimpTestFixture *fixture,
                                    &shell_y_after_zoom);
   factor_after_zoom = gimp_zoom_model_get_factor (shell->zoom);
 
-  /* First of all make sure a zoom happend at all */
+  /* First of all make sure a zoom happend at all. If this assert
+   * fails, it means that the zoom didn't happen. Possible causes:
+   *
+   *  * gdk_test_simulate_key() failed to map 'GDK_plus' to the proper
+   *    'plus' X keysym, probably because it is mapped to a keycode
+   *    with modifiers like 'shift'. Run "xmodmap -pk | grep plus" to
+   *    find out. Make sure 'plus' is the first keysym for the given
+   *    keycode. If not, use "xmodmap <keycode> = plus" to correct it.
+   */
   g_assert_cmpfloat (fabs (factor_before_zoom - factor_after_zoom),
                      >=,
                      GIMP_UI_ZOOM_EPSILON);