diff --git a/dom/traversal/TreeWalker-nextNode-detached-currentNode.window.js b/dom/traversal/TreeWalker-nextNode-detached-currentNode.window.js
new file mode 100644
index 00000000000000..bdb826d8fb3051
--- /dev/null
+++ b/dom/traversal/TreeWalker-nextNode-detached-currentNode.window.js
@@ -0,0 +1,27 @@
+test(() => {
+  const detached = document.createElement("div");
+  const walker = document.createTreeWalker(document, 0, null);
+  walker.currentNode = detached;
+  assert_equals(walker.nextNode(), null);
+}, "nextNode() returns null when currentNode is a detached element with no descendants and whatToShow does not match it");
+
+test(() => {
+  const detached = document.createElement("div");
+  detached.appendChild(document.createElement("span"));
+  const walker = document.createTreeWalker(document, NodeFilter.SHOW_ELEMENT, null);
+  walker.currentNode = detached;
+  assert_equals(walker.nextNode(), detached.firstChild);
+  assert_equals(walker.nextNode(), null);
+}, "nextNode() returns null after exhausting a detached subtree");
+
+test(() => {
+  const template = document.createElement("template");
+  template.innerHTML = "text<div></div>text";
+  const walker = document.createTreeWalker(
+    document,
+    NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_COMMENT,
+    null);
+  walker.currentNode = template.content;
+  assert_equals(walker.nextNode(), template.content.children[0]);
+  assert_equals(walker.nextNode(), null);
+}, "nextNode() terminates when iterating over template.content not under the walker's root");