1 files changed, 41 insertions, 0 deletions
diff --git a/dom/tests/mochitest/webcomponents/test_custom_element_upgrade.html b/dom/tests/mochitest/webcomponents/test_custom_element_upgrade.html
new file mode 100644
index 0000000000..5759925cfa
--- /dev/null
+++ b/dom/tests/mochitest/webcomponents/test_custom_element_upgrade.html
@@ -0,0 +1,41 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1299363
+-->
+<head>
+  <title>Test upgrade steps for custom elements.</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1299363">Bug 1299363</a>
+<script type="text/javascript">
+// Fake the Cu.waiveXrays, so that we can share the tests with mochitest chrome.
+var Cu = { waiveXrays: (obj) => obj };
+SimpleTest.waitForExplicitFinish();
+
+var promises = [];
+function test_with_new_window(f, msg) {
+  promises.push(new Promise((aResolve) => {
+    let iframe = document.createElement('iframe');
+    iframe.setAttribute('type', 'content');
+    iframe.setAttribute('src', 'test_upgrade_page.html');
+    iframe.onload = function() {
+      // Use window from iframe to isolate the test.
+      f(iframe.contentWindow, msg);
+      aResolve();
+    };
+    document.body.appendChild(iframe);
+  }));
+}
+</script>
+<!-- Test cases for autonomous element -->
+<script type="text/javascript" src="upgrade_tests.js"></script>
+<script>
+Promise.all(promises).then(() => {
+  SimpleTest.finish();
+});
+</script>
+</body>
+</html>
+\ No newline at end of file