onTs) {
    tr.model.ObjectInstance.call(
        this, parent, scopedId, category, name, creationTs);
  };

  TestObjectInstance.prototype = {
    __proto__: tr.model.ObjectInstance.prototype
  };

  test('objectInstanceSubtype', function() {
    // Register that TestObjects are bound to TestObjectInstance.
    tr.model.ObjectInstance.subTypes.register(
        TestObjectInstance,
        {typeName: 'TestObject'});

    try {
      const collection = new tr.model.ObjectCollection({ });
      const scopedId