[gtk/image-loading] testuite: Add opacity-overdraw test

[Benjamin Otte <otte src gnome org>]

commit b641eca072eb69b35a70c36dde641c28b949eeee
Author: Benjamin Otte <otte redhat com>
Date:   Wed Sep 15 07:37:57 2021 +0200

    testuite: Add opacity-overdraw test
    
    Tests that overdrawing of content inside an opacity node happens before
    the opacity is applied.
    
    This is broken in the GL renderer and causes the opacity.ui reftest to
    fail.

 testsuite/gsk/compare/opacity-overdraw.node |  15 +++++++++++++++
 testsuite/gsk/compare/opacity-overdraw.png  | Bin 0 -> 127 bytes
 testsuite/gsk/meson.build                   |   1 +
 3 files changed, 16 insertions(+)
---
diff --git a/testsuite/gsk/compare/opacity-overdraw.node b/testsuite/gsk/compare/opacity-overdraw.node
new file mode 100644
index 0000000000..78057f43a8
--- /dev/null
+++ b/testsuite/gsk/compare/opacity-overdraw.node
@@ -0,0 +1,15 @@
+opacity {
+  child: transform {
+    transform: translate(15, 15);
+    child: container {
+      color {
+        bounds: -15 -15 30 30;
+        color: rgb(0,0,255);
+      }
+      color {
+        bounds: -10 -10 20 20;
+        color: rgb(255,0,0);
+      }
+    }
+  }
+}
diff --git a/testsuite/gsk/compare/opacity-overdraw.png b/testsuite/gsk/compare/opacity-overdraw.png
new file mode 100644
index 0000000000..4499664e58
Binary files /dev/null and b/testsuite/gsk/compare/opacity-overdraw.png differ
diff --git a/testsuite/gsk/meson.build b/testsuite/gsk/meson.build
index e6901e5ef9..6e62938d7a 100644
--- a/testsuite/gsk/meson.build
+++ b/testsuite/gsk/meson.build
@@ -62,6 +62,7 @@ compare_render_tests = [
   'issue-3615',
   'nested-rounded-clips',
   'opacity_clip',
+  'opacity-overdraw',
   'opacity-overlapping-children',
   'outset_shadow_offset_both',
   'outset_shadow_offset_x',