2 files changed, 21 insertions, 0 deletions
diff --git a/testing/web-platform/tests/custom-state-pseudo-class/META.yml b/testing/web-platform/tests/custom-state-pseudo-class/META.yml
new file mode 100644
index 0000000000..ee34d8b900
--- /dev/null
+++ b/testing/web-platform/tests/custom-state-pseudo-class/META.yml
@@ -0,0 +1 @@
+spec: https://wicg.github.io/custom-state-pseudo-class/
diff --git a/testing/web-platform/tests/custom-state-pseudo-class/idlharness.window.js b/testing/web-platform/tests/custom-state-pseudo-class/idlharness.window.js
new file mode 100644
index 0000000000..d5d40c5461
--- /dev/null
+++ b/testing/web-platform/tests/custom-state-pseudo-class/idlharness.window.js
@@ -0,0 +1,20 @@
+// META: script=/resources/WebIDLParser.js
+// META: script=/resources/idlharness.js
+
+'use strict';
+
+class MyElement extends HTMLElement {};
+customElements.define('my-element', MyElement);
+
+idl_test(
+  ['custom-state-pseudo-class'],
+  ['html', 'wai-aria'],
+  idl_array => {
+    idl_array.add_objects({
+      CustomStateSet: [ 'customStateSet' ],
+    });
+
+    const myElement = document.createElement('my-element');
+    self.customStateSet = myElement.attachInternals().states;
+  }
+);