1 files changed, 38 insertions, 0 deletions
diff --git a/js/tests/unit/util.js b/js/tests/unit/util.js
index 61727304d..2fd6f6b7c 100644
--- a/js/tests/unit/util.js
+++ b/js/tests/unit/util.js
@@ -124,4 +124,42 @@ $(function () {
     assert.expect(1)
     assert.ok(Util.supportsTransitionEnd())
   })
+
+  QUnit.test('Util.findShadowRoot should find the shadow DOM root', function (assert) {
+    // Only for newer browsers
+    if (!document.documentElement.attachShadow) {
+      assert.expect(0)
+      return
+    }
+
+    assert.expect(2)
+    var $div = $('<div id="test"></div>').appendTo($('#qunit-fixture'))
+    var shadowRoot = $div[0].attachShadow({
+      mode: 'open'
+    })
+    console.warn($div[0].attachShadow, shadowRoot)
+
+    assert.equal(shadowRoot, Util.findShadowRoot(shadowRoot))
+    shadowRoot.innerHTML = '<button>Shadow Button</button>'
+    assert.equal(shadowRoot, Util.findShadowRoot(shadowRoot.firstChild))
+  })
+
+  QUnit.test('Util.findShadowRoot should return null when attachShadow is not available', function (assert) {
+    assert.expect(1)
+
+    var $div = $('<div id="test"></div>').appendTo($('#qunit-fixture'))
+    if (!document.documentElement.attachShadow) {
+      assert.equal(null, Util.findShadowRoot($div[0]))
+    } else {
+      var sandbox = sinon.createSandbox()
+
+      sandbox.replace(document.documentElement, 'attachShadow', function () {
+        // to avoid empty function
+        return $div
+      })
+
+      assert.equal(null, Util.findShadowRoot($div[0]))
+      sandbox.restore()
+    }
+  })
 })