1 files changed, 4 insertions, 0 deletions
diff --git a/testing/web-platform/tests/shadow-dom/declarative/support/helpers.js b/testing/web-platform/tests/shadow-dom/declarative/support/helpers.js
new file mode 100644
index 0000000000..0be3add620
--- /dev/null
+++ b/testing/web-platform/tests/shadow-dom/declarative/support/helpers.js
@@ -0,0 +1,4 @@
+function setInnerHTML(el,content) {
+  const fragment = (new DOMParser()).parseFromString(`<pre>${content}</pre>`, 'text/html', {includeShadowRoots: true});
+  (el instanceof HTMLTemplateElement ? el.content : el).replaceChildren(...fragment.body.firstChild.childNodes);
+}