diff --git a/static_src/elements/chops/chops-collapse/chops-collapse.test.js b/static_src/elements/chops/chops-collapse/chops-collapse.test.js
new file mode 100644
index 0000000..7058b65
--- /dev/null
+++ b/static_src/elements/chops/chops-collapse/chops-collapse.test.js
@@ -0,0 +1,33 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import {assert} from 'chai';
+import {ChopsCollapse} from './chops-collapse.js';
+
+
+let element;
+describe('chops-collapse', () => {
+  beforeEach(() => {
+    element = document.createElement('chops-collapse');
+    document.body.appendChild(element);
+  });
+
+  afterEach(() => {
+    document.body.removeChild(element);
+  });
+
+  it('initializes', () => {
+    assert.instanceOf(element, ChopsCollapse);
+  });
+
+  it('toggling chops-collapse changes aria-hidden', () => {
+    element.opened = true;
+
+    assert.isNull(element.getAttribute('aria-hidden'));
+
+    element.opened = false;
+
+    assert.isDefined(element.getAttribute('aria-hidden'));
+  });
+});