WebKit export of https://bugs.webkit.org/show_bug.cgi?id=237920 (#33229)

diff --git a/css/css-animations/parsing/animation-computed.html b/css/css-animations/parsing/animation-computed.html
index 467f435..f8d34b8 100644
--- a/css/css-animations/parsing/animation-computed.html
+++ b/css/css-animations/parsing/animation-computed.html
@@ -16,6 +16,11 @@
 // <single-animation-iteration-count> || <single-animation-direction> ||
 // <single-animation-fill-mode> || <single-animation-play-state> ||
 // [ none | <keyframes-name> ]
+
+test(() => {
+  assert_equals(getComputedStyle(document.getElementById('target')).animation, "0s ease 0s 1 normal none running none");
+}, "Default animation value");
+
 test_computed_value("animation", "1s", "1s ease 0s 1 normal none running none");
 test_computed_value("animation", "cubic-bezier(0, -2, 1, 3)", "0s cubic-bezier(0, -2, 1, 3) 0s 1 normal none running none");
 test_computed_value("animation", "1s -3s", "1s ease -3s 1 normal none running none");
diff --git a/css/css-transitions/parsing/transition-computed.html b/css/css-transitions/parsing/transition-computed.html
index 3f253c3..a825513 100644
--- a/css/css-transitions/parsing/transition-computed.html
+++ b/css/css-transitions/parsing/transition-computed.html
@@ -14,6 +14,11 @@
 <script>
 // <single-transition> = [ none | <single-transition-property> ] ||
 // <time> || <easing-function> || <time>
+
+test(() => {
+  assert_equals(getComputedStyle(document.getElementById('target')).transition, "all 0s ease 0s");
+}, "Default transition value");
+
 test_computed_value("transition", "1s", "all 1s ease 0s");
 test_computed_value("transition", "cubic-bezier(0, -2, 1, 3)", "all 0s cubic-bezier(0, -2, 1, 3) 0s");
 test_computed_value("transition", "1s -3s", "all 1s ease -3s");