diff --git a/resources/idlharness.js b/resources/idlharness.js
index 2d0d28c7b27201a..3bcbb8412e6daca 100644
--- a/resources/idlharness.js
+++ b/resources/idlharness.js
@@ -310,7 +310,7 @@ IdlArray.prototype.add_dependency_idls = function(raw_idls, options)
                     // members) is being tested.
                     if (dep_type !== "includes"
                         || inheriting in this.members && !this.members[inheriting].untested
-                        || this.partials.find(function(p) {
+                        || this.partials.some(function(p) {
                                 return p.name === inheriting;
                             })) {
                         deps.push(inheritor);