Add some tests for node diffing

Nothing deep yet, but more can be added.

testsuite/gsk/diff.c

@@ -0,0 +1,99 @@
+/*
+ * Copyright © 2021 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Matthias Clasen
+ */
+
+#include <gtk/gtk.h>
+#include "gsk/gskrendernodeprivate.h"
+
+static void
+test_can_diff_basic (void)
+{
+  GskRenderNode *container1, *container2;
+  GskRenderNode *color1, *color2;
+
+  color1 = gsk_color_node_new (&(GdkRGBA){0, 1, 0, 1 }, &GRAPHENE_RECT_INIT (0, 0, 10, 10));
+  color2 = gsk_color_node_new (&(GdkRGBA){1, 1, 0, 1 }, &GRAPHENE_RECT_INIT (0, 0, 10, 10));
+
+  container1 = gsk_container_node_new (&color1, 1);
+  container2 = gsk_container_node_new (&color2, 1);
+
+  /* We can diff two color nodes */
+  g_assert_true (gsk_render_node_can_diff (color1, color2));
+  /* We can diff two container nodes */
+  g_assert_true (gsk_render_node_can_diff (container1, container2));
+  /* We can diff container nodes against anything else */
+  g_assert_true (gsk_render_node_can_diff (container1, color2));
+  g_assert_true (gsk_render_node_can_diff (color1, container2));
+
+  gsk_render_node_unref (color1);
+  gsk_render_node_unref (color2);
+
+  gsk_render_node_unref (container1);
+  gsk_render_node_unref (container2);
+}
+
+static void
+test_can_diff_transform (void)
+{
+  GskRenderNode *color1, *color2;
+  GskRenderNode *opacity;
+  GskRenderNode *transform1, *transform2, *transform3, *transform4;
+  GskTransform *t1, *t2;
+
+  color1 = gsk_color_node_new (&(GdkRGBA){0, 1, 0, 1 }, &GRAPHENE_RECT_INIT (0, 0, 10, 10));
+  color2 = gsk_color_node_new (&(GdkRGBA){1, 1, 0, 1 }, &GRAPHENE_RECT_INIT (0, 0, 10, 10));
+  opacity = gsk_opacity_node_new (color2, 0.5);
+
+  t1 = gsk_transform_translate (NULL, &GRAPHENE_POINT_INIT (10, 10));
+  t2 = gsk_transform_scale (NULL, 2, 1);
+
+  transform1 = gsk_transform_node_new (color1, t1);
+  transform2 = gsk_transform_node_new (color2, t1);
+  transform3 = gsk_transform_node_new (color2, t2);
+  transform4 = gsk_transform_node_new (opacity, t1);
+
+  /* The case we can handle */
+  g_assert_true (gsk_render_node_can_diff (transform1, transform2));
+
+  /* These, we can't */
+  g_assert_false (gsk_render_node_can_diff (transform1, transform3));
+  g_assert_false (gsk_render_node_can_diff (transform1, transform4));
+
+  gsk_render_node_unref (color1);
+  gsk_render_node_unref (color2);
+  gsk_render_node_unref (opacity);
+  gsk_render_node_unref (transform1);
+  gsk_render_node_unref (transform2);
+  gsk_render_node_unref (transform3);
+  gsk_render_node_unref (transform4);
+
+  gsk_transform_unref (t1);
+  gsk_transform_unref (t2);
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  gtk_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/node/can-diff/basic", test_can_diff_basic);
+  g_test_add_func ("/node/can-diff/transform", test_can_diff_transform);
+
+  return g_test_run ();
+}

testsuite/gsk/meson.build

@@ -230,3 +230,36 @@ foreach t : tests
     suite: 'gsk',
   )
 endforeach
+
+internal_tests = [
+  ['diff']
+]
+
+foreach t : internal_tests
+  test_name = t.get(0)
+  test_srcs = ['@0@.c'.format(test_name)] + t.get(1, [])
+  test_extra_cargs = t.get(2, [])
+  test_extra_ldflags = t.get(3, [])
+
+  test_exe = executable(test_name, test_srcs,
+    c_args : test_cargs + test_extra_cargs + common_cflags,
+    link_args : test_extra_ldflags,
+    dependencies : libgtk_static_dep,
+    install: get_option('install-tests'),
+    install_dir: testexecdir,
+  )
+
+  test(test_name, test_exe,
+    args: [ '--tap', '-k' ],
+    protocol: 'tap',
+    env: [
+      'GSK_RENDERER=cairo',
+      'GTK_A11Y=test',
+      'G_TEST_SRCDIR=@0@'.format(meson.current_source_dir()),
+      'G_TEST_BUILDDIR=@0@'.format(meson.current_build_dir())
+    ],
+    suite: 'gsk',
+  )
+endforeach
+
+