[gtk] testsuite: Add a color matrix test case

[Timm Bäder <baedert src gnome org>]

commit 2979aea3ae674cbc1e318d1c884e86ededb17399
Author: Timm Bäder <mail baedert org>
Date:   Sat May 18 09:22:44 2019 +0200

    testsuite: Add a color matrix test case
    
    Color matrix nodes with an identity matrix and no offset should still
    produce the expected image.

 testsuite/gsk/compare/color-matrix-identity.node |   8 ++++++++
 testsuite/gsk/compare/color-matrix-identity.png  | Bin 0 -> 162 bytes
 testsuite/gsk/meson.build                        |   1 +
 3 files changed, 9 insertions(+)
---
diff --git a/testsuite/gsk/compare/color-matrix-identity.node 
b/testsuite/gsk/compare/color-matrix-identity.node
new file mode 100644
index 0000000000..a81a474ad0
--- /dev/null
+++ b/testsuite/gsk/compare/color-matrix-identity.node
@@ -0,0 +1,8 @@
+color-matrix {
+  child: color {
+    bounds: 0 0 50 50;
+    color: rgba(255, 0, 0, 0.5);
+  }
+  matrix: none;
+  offset: 0 0 0 0;
+}
diff --git a/testsuite/gsk/compare/color-matrix-identity.png b/testsuite/gsk/compare/color-matrix-identity.png
new file mode 100644
index 0000000000..f88dc6ac79
Binary files /dev/null and b/testsuite/gsk/compare/color-matrix-identity.png differ
diff --git a/testsuite/gsk/meson.build b/testsuite/gsk/meson.build
index 3150a2a59f..20851649b3 100644
--- a/testsuite/gsk/meson.build
+++ b/testsuite/gsk/meson.build
@@ -40,6 +40,7 @@ compare_render_tests = [
   'outset_shadow_simple',
   'shadow-in-opacity',
   'texture-url',
+  'color-matrix-identity',
 ]
 
 renderers = [