[gdk-pixbuf] tests: Check that pixbufs are valid before comparing them

[Philip Withnall <pwithnall src gnome org>]

commit 0f538573aca0950eac37a407aed5529f41019200
Author: Philip Withnall <withnall endlessm com>
Date:   Mon Feb 6 13:23:05 2017 +0000

    tests: Check that pixbufs are valid before comparing them
    
    Assert that the pixbufs have non-negative dimensions before comparing
    them and potentially using one of the dimensions as a loop bound.
    
    Coverity IDs: 1399711, 1399712
    
    https://bugzilla.gnome.org/show_bug.cgi?id=776990

 tests/pixbuf-scale-two-step.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/tests/pixbuf-scale-two-step.c b/tests/pixbuf-scale-two-step.c
index d80f155..8050b30 100644
--- a/tests/pixbuf-scale-two-step.c
+++ b/tests/pixbuf-scale-two-step.c
@@ -63,6 +63,11 @@ pixdata_almost_equal (GdkPixbuf *one, GdkPixbuf *two)
   guchar *two_pixel;    /* Pointer to current pixel data in two */
   guint x, y;
 
+  g_assert_cmpint (gdk_pixbuf_get_height (one), >=, 0);
+  g_assert_cmpint (gdk_pixbuf_get_width (one), >=, 0);
+  g_assert_cmpint (gdk_pixbuf_get_height (two), >=, 0);
+  g_assert_cmpint (gdk_pixbuf_get_width (two), >=, 0);
+
   if (gdk_pixbuf_get_width (one) != gdk_pixbuf_get_width (two) ||
       gdk_pixbuf_get_height (one) != gdk_pixbuf_get_height (two))
     {