mongodb/jstests/concurrency/fsm_example_inheritance.js

'use strict';

load('jstests/concurrency/fsm_libs/extend_workload.js');  // for extendWorkload
load('jstests/concurrency/fsm_example.js');  // for $config

// extendWorkload takes a $config object and a callback, and returns an extended $config object.
var $config = extendWorkload($config,
                             function($config, $super) {
                                 // In the callback, $super is the base workload definition we're
                                 // extending,
                                 // and $config is the extended workload definition we're creating.

                                 // You can replace any properties on $config, including methods you
                                 // want to override.
                                 $config.setup = function(db, collName, cluster) {
                                     // Overridden methods should usually call the corresponding
                                     // method on $super.
                                     $super.setup.apply(this, arguments);

                                     db[collName].ensureIndex({exampleIndexedField: 1});
                                 };

                                 return $config;
                             });