Add tests for css value transitions

Just a few cases for now, enough to test a recently
fixed regression with shadow transitions.

testsuite/css/meson.build

@@ -44,6 +44,20 @@ test('data', test_data,
   suite: 'css',
 )
 
+test_parser = executable('test-css-value', 'test-css-value.c',
+  c_args: common_cflags,
+  dependencies: libgtk_static_dep,
+  install: get_option('install-tests'),
+  install_dir: testexecdir,
+)
+
+test('css value', test_parser,
+     args: [ '--tap', '-k' ],
+     protocol: 'tap',
+     env: csstest_env,
+     suite: 'css'
+)
+
 if get_option('install-tests')
   conf = configuration_data()
   conf.set('libexecdir', gtk_libexecdir)

testsuite/css/test-css-value.c

@@ -0,0 +1,166 @@
+/*
+ * Copyright (C) 2021 Red Hat Inc.
+ *
+ * Author:
+ *      Matthias Clasen <mclasen@redhat.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <gtk/gtk.h>
+#include "gtk/gtkcssvalueprivate.h"
+#include "gtk/gtkcsscolorvalueprivate.h"
+#include "gtk/gtkcssstylepropertyprivate.h"
+
+static gboolean
+color_is_near (const GdkRGBA *color1,
+               const GdkRGBA *color2)
+{
+  if (fabs (color1->red - color2->red) > FLT_EPSILON)
+    return FALSE;
+  if (fabs (color1->green - color2->green) > FLT_EPSILON)
+    return FALSE;
+  if (fabs (color1->blue- color2->blue) > FLT_EPSILON)
+    return FALSE;
+  if (fabs (color1->alpha- color2->alpha) > FLT_EPSILON)
+    return FALSE;
+  return TRUE;
+}
+
+static gboolean
+value_is_near (int          prop,
+               GtkCssValue *value1,
+               GtkCssValue *value2)
+{
+  if (_gtk_css_value_equal (value1, value2))
+    return TRUE;
+
+  switch (prop)
+    {
+    case GTK_CSS_PROPERTY_COLOR:
+      {
+        GtkCssValue *v1, *v2;
+        const GdkRGBA *c1, *c2;
+        gboolean res;
+
+        v1 = _gtk_css_value_compute (value1, prop, NULL, NULL, NULL);
+        v2 = _gtk_css_value_compute (value2, prop, NULL, NULL, NULL);
+        c1 = gtk_css_color_value_get_rgba (v1);
+        c2 = gtk_css_color_value_get_rgba (v2);
+
+        res = color_is_near (c1, c2);
+
+        gtk_css_value_unref (v1);
+        gtk_css_value_unref (v2);
+
+        return res;
+      }
+      break;
+
+    default:
+      break;
+    }
+
+  return FALSE;
+}
+
+typedef struct {
+  int prop;
+  const char *value1;
+  const char *value2;
+  double progress;
+  const char *expected;
+} ValueTransitionTest;
+
+static ValueTransitionTest tests[] = {
+  { GTK_CSS_PROPERTY_COLOR, "transparent", "rgb(255,0,0)", 0.25, "rgba(255,0,0,0.25)" },
+  { GTK_CSS_PROPERTY_BOX_SHADOW, "none", "2px 2px 10px 4px rgb(200,200,200)", 0.5, "1px 1px 5px 2px rgb(100,100,100)" },
+  { GTK_CSS_PROPERTY_BOX_SHADOW, "2px 2px 10px 4px rgb(200,200,200)", "none", 0.5, "1px 1px 5px 2px rgb(100,100,100)" },
+};
+
+static void
+test_transition (gconstpointer data)
+{
+  ValueTransitionTest *test = &tests[GPOINTER_TO_INT (data)];
+  GtkStyleProperty *prop;
+  GtkCssValue *value1;
+  GtkCssValue *value2;
+  GtkCssValue *expected;
+  GtkCssValue *result;
+  GtkCssParser *parser;
+  GBytes *bytes;
+
+  prop = (GtkStyleProperty *)_gtk_css_style_property_lookup_by_id (test->prop);
+
+  bytes = g_bytes_new_static (test->value1, strlen (test->value1));
+  parser = gtk_css_parser_new_for_bytes (bytes, NULL, NULL, NULL, NULL, NULL);
+  value1 = _gtk_style_property_parse_value (prop, parser);
+  gtk_css_parser_unref (parser);
+  g_bytes_unref (bytes);
+
+  bytes = g_bytes_new_static (test->value1, strlen (test->value2));
+  parser = gtk_css_parser_new_for_bytes (bytes, NULL, NULL, NULL, NULL, NULL);
+  value2 = _gtk_style_property_parse_value (prop, parser);
+  gtk_css_parser_unref (parser);
+  g_bytes_unref (bytes);
+
+  bytes = g_bytes_new_static (test->value1, strlen (test->expected));
+  parser = gtk_css_parser_new_for_bytes (bytes, NULL, NULL, NULL, NULL, NULL);
+  expected = _gtk_style_property_parse_value (prop, parser);
+  gtk_css_parser_unref (parser);
+  g_bytes_unref (bytes);
+
+  result = _gtk_css_value_transition (value1, value2, test->prop, test->progress);
+  g_assert_true (value_is_near (test->prop, result, expected));
+
+  gtk_css_value_unref (value1);
+  gtk_css_value_unref (value2);
+  gtk_css_value_unref (expected);
+  gtk_css_value_unref (result);
+}
+
+int
+main (int argc, char **argv)
+{
+  GtkStyleProperty *previous;
+  int j;
+
+  gtk_test_init (&argc, &argv);
+
+  previous = NULL;
+  j = 0;
+  for (int i = 0; i < G_N_ELEMENTS (tests); i++)
+    {
+      ValueTransitionTest *test = &tests[i];
+      GtkStyleProperty *prop;
+      char *path;
+
+      prop = (GtkStyleProperty *)_gtk_css_style_property_lookup_by_id (test->prop);
+      if (prop != previous)
+        {
+          previous = prop;
+          j = 0;
+        }
+      else
+        j++;
+
+      path = g_strdup_printf ("/css/value/transition/%s/%d", _gtk_style_property_get_name ((GtkStyleProperty *)prop), j);
+      g_test_add_data_func (path, GINT_TO_POINTER (i), test_transition);
+      g_free (path);
+    }
+
+  return g_test_run ();
+}