diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index 2176f9ef317..3e6746c6922 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -39677,12 +39677,42 @@
     "deleted_reftests": {},
     "items": {
       "testharness": {
+        "cssom/CSSKeyframesRule.html": [
+          {
+            "path": "cssom/CSSKeyframesRule.html",
+            "url": "/cssom/CSSKeyframesRule.html"
+          }
+        ],
+        "cssom/CSSNamespaceRule.html": [
+          {
+            "path": "cssom/CSSNamespaceRule.html",
+            "url": "/cssom/CSSNamespaceRule.html"
+          }
+        ],
+        "cssom/CSSRuleList.html": [
+          {
+            "path": "cssom/CSSRuleList.html",
+            "url": "/cssom/CSSRuleList.html"
+          }
+        ],
+        "cssom/CSSStyleSheet.html": [
+          {
+            "path": "cssom/CSSStyleSheet.html",
+            "url": "/cssom/CSSStyleSheet.html"
+          }
+        ],
         "cssom/MediaList.html": [
           {
             "path": "cssom/MediaList.html",
             "url": "/cssom/MediaList.html"
           }
         ],
+        "cssom/StyleSheetList.html": [
+          {
+            "path": "cssom/StyleSheetList.html",
+            "url": "/cssom/StyleSheetList.html"
+          }
+        ],
         "cssom/shorthand-serialization.html": [
           {
             "path": "cssom/shorthand-serialization.html",
diff --git a/tests/wpt/web-platform-tests/cssom/CSSKeyframesRule.html b/tests/wpt/web-platform-tests/cssom/CSSKeyframesRule.html
new file mode 100644
index 00000000000..b97d988c9ac
--- /dev/null
+++ b/tests/wpt/web-platform-tests/cssom/CSSKeyframesRule.html
@@ -0,0 +1,58 @@
+<!doctype html>
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>CSSOM -  CSSKeyframesRule interface</title>
+    <script src="/resources/testharness.js"></script>
+    <script src="/resources/testharnessreport.js"></script>
+    <style>
+        @keyframes foo {
+            0% { top: 0px; }
+            100% { top: 200px; }
+        }
+    </style>
+
+    <script>
+    test(function () {
+        var keyframe = document.styleSheets[0].cssRules[0];
+        assert_equals(keyframe.cssRules.length, 2, "CSSKeyframesRule cssRule length attribute");
+        assert_equals(keyframe.cssRules[0].cssText, "0% { top: 0px; }", "CSSKeyframesRule cssRule cssText attribute");
+        assert_equals(keyframe.cssRules[1].cssText, "100% { top: 200px; }", "CSSKeyframesRule cssRule cssText attribute");
+
+        keyframe.appendRule("50% { top: 100px; }");
+        assert_equals(keyframe.cssRules.length, 3, "CSSKeyframesRule prefix attribute after appendRule function");
+        assert_equals(keyframe.cssRules[0].cssText, "0% { top: 0px; }", "CSSKeyframesRule cssRule cssText attribute after appendRule function");
+        assert_equals(keyframe.cssRules[1].cssText, "100% { top: 200px; }", "CSSKeyframesRule cssRule cssText attribute after appendRule function");
+        assert_equals(keyframe.cssRules[2].cssText, "50% { top: 100px; }", "CSSKeyframesRule cssRule cssText attribute after appendRule function");
+
+        keyframe.appendRule("0% { top: 50px; }");
+        assert_equals(keyframe.cssRules.length, 4, "CSSKeyframesRule prefix attribute after appendRule function");
+        assert_equals(keyframe.cssRules[0].cssText, "0% { top: 0px; }", "CSSKeyframesRule cssRule cssText attribute after appendRule function");
+        assert_equals(keyframe.cssRules[1].cssText, "100% { top: 200px; }", "CSSKeyframesRule cssRule cssText attribute after appendRule function");
+        assert_equals(keyframe.cssRules[2].cssText, "50% { top: 100px; }", "CSSKeyframesRule cssRule cssText attribute after appendRule function");
+        assert_equals(keyframe.cssRules[3].cssText, "0% { top: 50px; }", "CSSKeyframesRule cssRule cssText attribute after appendRule function");
+
+        var find1 = keyframe.findRule("50%");
+        assert_equals(find1.cssText, "50% { top: 100px; }", "CSSKeyframesRule findRule function");
+        var find2 = keyframe.findRule("0%");
+        assert_equals(find2.cssText, "0% { top: 50px; }", "CSSKeyframesRule findRule function");
+        var find3 = keyframe.findRule("70%");
+        assert_equals(find3, null, "CSSKeyframesRule findRule function");
+
+        keyframe.deleteRule("100%");
+        assert_equals(keyframe.cssRules.length, 3, "CSSKeyframesRule prefix attribute after deleteRule function");
+        assert_equals(keyframe.cssRules[0].cssText, "0% { top: 0px; }", "CSSKeyframesRule cssRule cssText attribute after deleteRule function");
+        assert_equals(keyframe.cssRules[1].cssText, "50% { top: 100px; }", "CSSKeyframesRule cssRule cssText attribute after deleteRule function");
+        assert_equals(keyframe.cssRules[2].cssText, "0% { top: 50px; }", "CSSKeyframesRule cssRule cssText attribute after deleteRule function");
+        assert_equals(keyframe.cssRules[3], undefined, "CSSKeyframesRule cssRule cssText attribute after deleteRule function");
+
+        keyframe.deleteRule("80%");
+        assert_equals(keyframe.cssRules.length, 3, "CSSKeyframesRule prefix attribute after deleteRule function");
+        assert_equals(keyframe.cssRules[0].cssText, "0% { top: 0px; }", "CSSKeyframesRule cssRule cssText attribute after deleteRule function");
+        assert_equals(keyframe.cssRules[1].cssText, "50% { top: 100px; }", "CSSKeyframesRule cssRule cssText attribute after deleteRule function");
+        assert_equals(keyframe.cssRules[2].cssText, "0% { top: 50px; }", "CSSKeyframesRule cssRule cssText attribute after deleteRule function");
+        assert_equals(keyframe.cssRules[3], undefined, "CSSKeyframesRule cssRule cssText attribute after deleteRule function");
+    });
+    </script>
+</head>
+</html>
diff --git a/tests/wpt/web-platform-tests/cssom/CSSNamespaceRule.html b/tests/wpt/web-platform-tests/cssom/CSSNamespaceRule.html
new file mode 100644
index 00000000000..64ed94b6e7f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/cssom/CSSNamespaceRule.html
@@ -0,0 +1,31 @@
+<!doctype html>
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>CSSOM - CSSNamespaceRule interface</title>
+    <script src="/resources/testharness.js"></script>
+    <script src="/resources/testharnessreport.js"></script>
+    <style>
+        @namespace svg url(http://servo);
+        @namespace url(http://servo1);
+        @namespace svg url("http://servo2");
+    </style>
+
+    <script>
+    test(function () {
+        var rules = document.styleSheets[0].cssRules;
+        assert_equals(rules[0].prefix, "svg", "CSSNamespaceRule prefix attribute");
+        assert_equals(rules[0].namespaceURI, "http://servo", "CSSNamespaceRule namespaceURI attribute");
+        assert_equals(rules[0].cssText, "@namespace svg url(\"http://servo\");", "CSSNamespaceRule cssText attribute");
+
+        assert_equals(rules[1].prefix, "", "CSSNamespaceRule prefix attribute");
+        assert_equals(rules[1].namespaceURI, "http://servo1", "CSSNamespaceRule namespaceURI attribute");
+        assert_equals(rules[1].cssText, "@namespace url(\"http://servo1\");", "CSSNamespaceRule cssText attribute");
+
+        assert_equals(rules[2].prefix, "svg", "CSSNamespaceRule prefix attribute");
+        assert_equals(rules[2].namespaceURI, "http://servo2", "CSSNamespaceRule namespaceURI attribute");
+        assert_equals(rules[2].cssText, "@namespace svg url(\"http://servo2\");", "CSSNamespaceRule cssText attribute");
+    });
+    </script>
+</head>
+</html>
diff --git a/tests/wpt/web-platform-tests/cssom/CSSRuleList.html b/tests/wpt/web-platform-tests/cssom/CSSRuleList.html
new file mode 100644
index 00000000000..a394779617d
--- /dev/null
+++ b/tests/wpt/web-platform-tests/cssom/CSSRuleList.html
@@ -0,0 +1,26 @@
+<!doctype html>
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>CSSOM - CSSRuleList interface</title>
+    <script src="/resources/testharness.js"></script>
+    <script src="/resources/testharnessreport.js"></script>
+    <style>
+        body { width: 50%; }
+        #foo { height: 100px; }
+    </style>
+
+    <script>
+    test(function () {
+        var ruleList = document.styleSheets[0].cssRules;
+        assert_equals(ruleList.length, 2, "CSSRuleList length attribute");
+        assert_equals(ruleList[0].cssText, "body { width: 50%; }", "CSSRuleList indexed getter");
+        assert_equals(ruleList[1].cssText, "#foo { height: 100px; }", "CSSRuleList indexed getter");
+        assert_equals(ruleList[2], undefined, "CSSRuleList indexed getter");
+        assert_equals(ruleList.item(0).cssText, "body { width: 50%; }", "CSSRuleList item function");
+        assert_equals(ruleList.item(1).cssText, "#foo { height: 100px; }", "CSSRuleList item function");
+        assert_equals(ruleList.item(2), null, "CSSRuleList item function");
+    });
+    </script>
+</head>
+</html>
diff --git a/tests/wpt/web-platform-tests/cssom/CSSStyleSheet.html b/tests/wpt/web-platform-tests/cssom/CSSStyleSheet.html
new file mode 100644
index 00000000000..62ad133d5f6
--- /dev/null
+++ b/tests/wpt/web-platform-tests/cssom/CSSStyleSheet.html
@@ -0,0 +1,43 @@
+<!doctype html>
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>CSSOM - CSSStyleSheet interface</title>
+    <script src="/resources/testharness.js"></script>
+    <script src="/resources/testharnessreport.js"></script>
+    <style id="my-stylesheet">
+        body { width: 50%; }
+        #foo { height: 100px; }
+    </style>
+
+    <script>
+    test(function () {
+        var styleSheet = document.styleSheets[0];
+        styleSheet.cssRules[0].randomProperty = 1;
+        styleSheet.cssRules[1].randomProperty = 2;
+
+        assert_equals(styleSheet, document.getElementById("my-stylesheet").sheet, "CSSStyleSheet and LinkStyle's sheet attribute");
+        assert_equals(styleSheet.cssRules.length, 2, "CSSStyleSheet cssRules attribute");
+        assert_equals(styleSheet.cssRules[0].cssText, "body { width: 50%; }", "CSSStyleSheet cssRules attribute");
+        assert_equals(styleSheet.cssRules[1].cssText, "#foo { height: 100px; }", "CSSStyleSheet cssRules attribute");
+        assert_equals(styleSheet.cssRules[2], undefined, "CSSStyleSheet cssRules attribute");
+
+        styleSheet.insertRule("#bar { margin: 10px; }", 1);
+        assert_equals(styleSheet.cssRules.length, 3, "CSSStyleSheet cssRules attribute after insertRule function");
+        assert_equals(styleSheet.cssRules[0].cssText, "body { width: 50%; }", "CSSStyleSheet cssRules attribute");
+        assert_equals(styleSheet.cssRules[1].cssText, "#bar { margin: 10px; }", "CSSStyleSheet cssRules attribute after insertRule function");
+        assert_equals(styleSheet.cssRules[2].cssText, "#foo { height: 100px; }", "CSSStyleSheet cssRules attribute after insertRule function");
+        assert_equals(styleSheet.cssRules[0].randomProperty, 1, "[SameObject] cssRules attribute after insertRule function");
+        assert_equals(styleSheet.cssRules[2].randomProperty, 2, "[SameObject] cssRules attribute after insertRule function");
+
+        styleSheet.deleteRule(1);
+        assert_equals(styleSheet.cssRules.length, 2, "CSSStyleSheet cssRules attribute after deleteRule function");
+        assert_equals(styleSheet.cssRules[0].cssText, "body { width: 50%; }", "CSSStyleSheet cssRules attribute after deleteRule function");
+        assert_equals(styleSheet.cssRules[1].cssText, "#foo { height: 100px; }", "CSSStyleSheet cssRules attribute after deleteRule function");
+        assert_equals(styleSheet.cssRules[2], undefined, "CSSStyleSheet cssRules attribute after deleteRule function");
+        assert_equals(styleSheet.cssRules[0].randomProperty, 1, "[SameObject] cssRules attribute after deleteRule function");
+        assert_equals(styleSheet.cssRules[1].randomProperty, 2, "[SameObject] cssRules attribute after deleteRule function");
+    });
+    </script>
+</head>
+</html>
diff --git a/tests/wpt/web-platform-tests/cssom/StyleSheetList.html b/tests/wpt/web-platform-tests/cssom/StyleSheetList.html
new file mode 100644
index 00000000000..358264009a4
--- /dev/null
+++ b/tests/wpt/web-platform-tests/cssom/StyleSheetList.html
@@ -0,0 +1,33 @@
+<!doctype html>
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>CSSOM - StyleSheetList interface</title>
+    <script src="/resources/testharness.js"></script>
+    <script src="/resources/testharnessreport.js"></script>
+    <style>
+        body { width: 50%; }
+    </style>
+    <style>
+        #foo { width: 10%; }
+        #bar { height: 100px; }
+    </style>
+    <script>
+    test(function () {
+        var styleSheets = document.styleSheets;
+        assert_equals(styleSheets.length, 2, "StyleSheetList length attribute");
+        assert_equals(styleSheets[0].cssRules.length, 1, "StyleSheetList indexed getter length attribute");
+        assert_equals(styleSheets[1].cssRules.length, 2, "StyleSheetList indexed getter length attribute");
+        assert_equals(styleSheets[2], undefined, "StyleSheetList indexed getter length attribute");
+        assert_equals(styleSheets.item(0).cssRules.length, 1, "StyleSheetList item function length attribute");
+        assert_equals(styleSheets.item(1).cssRules.length, 2, "StyleSheetList item function length attribute");
+        assert_equals(styleSheets.item(2), null, "StyleSheetList item function length attribute");
+
+        styleSheets[0].randomProperty = 1;
+        var style = document.createElement("style");
+        document.head.appendChild(style);
+        assert_equals(styleSheets[0].randomProperty, 1, "[SameObject] StyleSheetList");
+    });
+    </script>
+</head>
+</html>
