<!DOCTYPE html>
<meta charset="utf-8">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<!-- Regression test for https://github.com/jsdom/jsdom/issues/3290 -->

<body>
<script>
"use strict";

test(() => {
  let innerConnectedCallbackCalled = false;
  customElements.define("inner-element", class extends HTMLElement {
    connectedCallback() {
      innerConnectedCallbackCalled = true;
    }
  });

  let outerConnectedCallbackCalled = false;
  customElements.define("outer-element", class extends HTMLElement {
    connectedCallback() {
      const template = document.createElement("template");
      template.innerHTML = "<inner-element></inner-element>";
      this.appendChild(document.importNode(template.content, true));
      outerConnectedCallbackCalled = true;
    }
  });

  document.body.appendChild(document.createElement("outer-element"));
  assert_true(innerConnectedCallbackCalled, "inner connectedCallback must be called");
  assert_true(outerConnectedCallbackCalled, "outer connectedCallback must be called");
}, "Nested custom element connectedCallback insertion involving a template DocumentFragment");
</script>