diff --git a/testing/web-platform/tests/content-security-policy/nonce-hiding/nonces.html b/testing/web-platform/tests/content-security-policy/nonce-hiding/nonces.html
new file mode 100644
index 0000000000000..e7bada96f94f8
--- /dev/null
+++ b/testing/web-platform/tests/content-security-policy/nonce-hiding/nonces.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id=log></div>
+<script>
+[["meh", ""],
+ ["div", ""],
+ ["script", ""],
+ ["meh", "http://www.w3.org/2000/svg"],
+ ["svg", "http://www.w3.org/2000/svg"], ,
+ ["script", "http://www.w3.org/2000/svg"]].forEach(([localName, namespace]) => {
+  test(t => {
+    const element = namespace === "" ? document.createElement(localName) : document.createElementNS(namespace, localName);
+    t.add_cleanup(() => element.remove());
+    assert_equals(element.nonce, "", "Initial IDL attribute value");
+    element.setAttribute("nonce", "x");
+    assert_equals(element.nonce, "x", "IDL attribute is modified after content attribute set");
+    assert_equals(element.getAttribute("nonce"), "x", "Content attribute is modified after content attribute set");
+    document.body.appendChild(element);
+    assert_equals(element.nonce, "x", "IDL attribute is unchanged after element insertion");
+    assert_equals(element.getAttribute("nonce"), "", "Content attribute is changed after element insertion");
+  }, `Basic nonce tests for ${localName} in ${namespace === "" ? "HTML" : "SVG"} namespace`);
+
+  test(t => {
+    const element = namespace === "" ? document.createElement(localName) : document.createElementNS(namespace, localName);
+    element.setAttribute("nonce", "x");
+    assert_equals(element.nonce, "x", "IDL attribute is modified after content attribute set");
+    element.removeAttribute("nonce");
+    assert_equals(element.nonce, "", "IDL attribute is empty after content attribute removal");
+  }, `Ensure that removal of content attribute does not affect IDL attribute for ${localName} in ${namespace === "" ? "HTML" : "SVG"} namespace`);
+});
+</script>
diff --git a/testing/web-platform/tests/content-security-policy/nonce-hiding/nonces.html.headers b/testing/web-platform/tests/content-security-policy/nonce-hiding/nonces.html.headers
new file mode 100644
index 0000000000000..daf482b5aba4f
--- /dev/null
+++ b/testing/web-platform/tests/content-security-policy/nonce-hiding/nonces.html.headers
@@ -0,0 +1 @@
+Content-Security-Policy: img-src 'none'
diff --git a/testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden-meta.tentative.sub.html b/testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden-meta.sub.html
similarity index 91%
rename from testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden-meta.tentative.sub.html
rename to testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden-meta.sub.html
index b15fcfa30b5ae..f8e5b946f0002 100644
--- a/testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden-meta.tentative.sub.html
+++ b/testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden-meta.sub.html
@@ -72,6 +72,8 @@
       var s = document.createElement('script');
       s.innerText = script.innerText;
       s.nonce = 'abc';
+      assert_equals(s.nonce, 'abc');
+      assert_equals(s.getAttribute('nonce'), null);
       document.head.appendChild(s);
       assert_equals(s.nonce, 'abc');
       assert_equals(s.getAttribute('nonce'), null);
@@ -119,12 +121,11 @@
     #cssTest[nonce=abc] { background: url(/security/resources/abe.png); }
 </style>
 <script nonce="abc" id="cssTest">
-    async_test(t => {
-      requestAnimationFrame(t.step_func_done(_ => {
-        var script = document.querySelector('#cssTest');
-        var style = getComputedStyle(script);
-        assert_equals(style['display'], 'block');
-        assert_equals(style['background-image'], "url(\"http://{{domains[]}}:{{ports[http][0]}}/security/resources/abe.png\")");
-      }));
+    test(t => {
+      const script = document.querySelector('#cssTest');
+      t.add_cleanup(() => script.remove());
+      var style = getComputedStyle(script);
+      assert_equals(style['display'], 'block');
+      assert_equals(style['background-image'], "url(\"http://{{domains[]}}:{{ports[http][0]}}/security/resources/abe.png\")");
     }, "Nonces leak via CSS side-channels.");
 </script>
diff --git a/testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden.tentative.html b/testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden.html
similarity index 93%
rename from testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden.tentative.html
rename to testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden.html
index 4b717b9b2a04b..b32635ff65817 100644
--- a/testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden.tentative.html
+++ b/testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden.html
@@ -73,6 +73,8 @@
       var s = document.createElement('script');
       s.innerText = script.innerText;
       s.nonce = 'abc';
+      assert_equals(s.nonce, 'abc');
+      assert_equals(s.getAttribute('nonce'), null);
       document.head.appendChild(s);
       assert_equals(s.nonce, 'abc');
       assert_equals(s.getAttribute('nonce'), null);
@@ -160,12 +162,11 @@
     #cssTest[nonce=abc] { background: url(/security/resources/abe.png); }
 </style>
 <script nonce="abc" id="cssTest">
-    async_test(t => {
-      requestAnimationFrame(t.step_func_done(_ => {
-        var script = document.querySelector('#cssTest');
-        var style = getComputedStyle(script);
-        assert_equals(style['display'], 'block');
-        assert_equals(style['background-image'], 'none');
-      }));
+    test(t => {
+      const script = document.querySelector('#cssTest');
+      t.add_cleanup(() => script.remove());
+      var style = getComputedStyle(script);
+      assert_equals(style['display'], 'block');
+      assert_equals(style['background-image'], 'none');
     }, "Nonces don't leak via CSS side-channels.");
 </script>
diff --git a/testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden.tentative.html.headers b/testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden.html.headers
similarity index 100%
rename from testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden.tentative.html.headers
rename to testing/web-platform/tests/content-security-policy/nonce-hiding/script-nonces-hidden.html.headers
diff --git a/testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden-meta.tentative.sub.html b/testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden-meta.sub.html
similarity index 84%
rename from testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden-meta.tentative.sub.html
rename to testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden-meta.sub.html
index bd1c33760d083..0bdf2ab8f488b 100644
--- a/testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden-meta.tentative.sub.html
+++ b/testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden-meta.sub.html
@@ -96,21 +96,3 @@
       assert_equals(innerScript.getAttribute('nonce'), 'abc', "Post-insertion content");
     }, "createElement.setAttribute.");
 </script>
-
-<!-- CSS Leakage -->
-<style>
-    #cssTest { display: block; }
-    #cssTest[nonce=abc] { background: url(/security/resources/abe.png); }
-</style>
-<svg xmlns="http://www.w3.org/2000/svg">
-  <script nonce="abc" id="cssTest">
-      async_test(t => {
-        requestAnimationFrame(t.step_func_done(_ => {
-          var script = document.querySelector('#cssTest');
-          var style = getComputedStyle(script);
-          assert_equals(style['display'], 'block');
-          assert_equals(style['background-image'], "url(\"http://{{domains[]}}:{{ports[http][0]}}/security/resources/abe.png\")");
-        }));
-      }, "Nonces don't leak via CSS side-channels.");
-  </script>
-</svg>
diff --git a/testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden.tentative.html b/testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden.html
similarity index 85%
rename from testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden.tentative.html
rename to testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden.html
index 8c0e58b1d1d24..d6e9379d4710b 100644
--- a/testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden.tentative.html
+++ b/testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden.html
@@ -96,21 +96,3 @@
       assert_equals(innerScript.getAttribute('nonce'), '', "Post-insertion content");
     }, "createElement.setAttribute.");
 </script>
-
-<!-- CSS Leakage -->
-<style>
-    #cssTest { display: block; }
-    #cssTest[nonce=abc] { background: url(/security/resources/abe.png); }
-</style>
-<svg xmlns="http://www.w3.org/2000/svg">
-  <script nonce="abc" id="cssTest">
-      async_test(t => {
-        requestAnimationFrame(t.step_func_done(_ => {
-          var script = document.querySelector('#cssTest');
-          var style = getComputedStyle(script);
-          assert_equals(style['display'], 'block');
-          assert_equals(style['background-image'], 'none');
-        }));
-      }, "Nonces don't leak via CSS side-channels.");
-  </script>
-</svg>
diff --git a/testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden.tentative.html.headers b/testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden.html.headers
similarity index 100%
rename from testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden.tentative.html.headers
rename to testing/web-platform/tests/content-security-policy/nonce-hiding/svgscript-nonces-hidden.html.headers
