1 files changed, 15 insertions, 0 deletions
diff --git a/tests/wpt/web-platform-tests/css/support/inheritance-testcommon.js b/tests/wpt/web-platform-tests/css/support/inheritance-testcommon.js
index 9f59cbbb6de..9229f1268ea 100644
--- a/tests/wpt/web-platform-tests/css/support/inheritance-testcommon.js
+++ b/tests/wpt/web-platform-tests/css/support/inheritance-testcommon.js
@@ -1,7 +1,10 @@
 'use strict';
 
+(function() {
+
 function assert_initial(property, initial) {
   test(() => {
+    const target = document.getElementById('target');
     if (!getComputedStyle(target)[property])
       return;
     target.style[property] = 'initial';
@@ -13,6 +16,8 @@ function assert_initial(property, initial) {
 /**
  * Create tests that a CSS property inherits and has the given initial value.
  *
+ * The current document must have an element #target within element #container.
+ *
  * @param {string} property  The name of the CSS property being tested.
  * @param {string} initial   The computed value for 'initial'.
  * @param {string} other     An arbitrary value for the property that round
@@ -22,6 +27,8 @@ function assert_inherited(property, initial, other) {
   assert_initial(property, initial);
 
   test(() => {
+    const container = document.getElementById('container');
+    const target = document.getElementById('target');
     if (!getComputedStyle(target)[property])
       return;
     container.style[property] = 'initial';
@@ -45,6 +52,8 @@ function assert_inherited(property, initial, other) {
  * Create tests that a CSS property does not inherit, and that it has the
  * given initial value.
  *
+ * The current document must have an element #target within element #container.
+ *
  * @param {string} property  The name of the CSS property being tested.
  * @param {string} initial   The computed value for 'initial'.
  * @param {string} other     An arbitrary value for the property that round
@@ -54,6 +63,8 @@ function assert_not_inherited(property, initial, other) {
   assert_initial(property, initial);
 
   test(() => {
+    const container = document.getElementById('container');
+    const target = document.getElementById('target');
     if (!getComputedStyle(target)[property])
       return;
     container.style[property] = 'initial';
@@ -69,3 +80,7 @@ function assert_not_inherited(property, initial, other) {
     target.style[property] = '';
   }, 'Property ' + property + ' does not inherit');
 }
+
+window.assert_inherited = assert_inherited;
+window.assert_not_inherited = assert_not_inherited;
+})();