diff --git a/webidl/ecmascript-binding/legacy-factory-function-builtin-properties.window.js b/webidl/ecmascript-binding/legacy-factory-function-builtin-properties.window.js
new file mode 100644
index 00000000000000..fc5c48aca380c0
--- /dev/null
+++ b/webidl/ecmascript-binding/legacy-factory-function-builtin-properties.window.js
@@ -0,0 +1,6 @@
+"use strict";
+
+test(() => {
+  const ownPropKeys = Reflect.ownKeys(Image).slice(0, 3);
+  assert_array_equals(ownPropKeys, ["length", "name", "prototype"]);
+}, 'Legacy factory function property enumeration order of "length", "name", and "prototype"');