diff --git a/mediacapture-insertable-streams/idlharness.any.js b/mediacapture-insertable-streams/idlharness.any.js
index d7975ab90fa7dc..594753cc1abcfd 100644
--- a/mediacapture-insertable-streams/idlharness.any.js
+++ b/mediacapture-insertable-streams/idlharness.any.js
@@ -7,6 +7,7 @@ idl_test(
   ['dom', 'html'],
   idl_array => {
     idl_array.add_objects({
+      MediaStreamTrackProcessor: ['new MediaStreamTrackProcessor({ track: new VideoTrackGenerator() })'],
       VideoTrackGenerator: ['new VideoTrackGenerator()'],
     });
   }