text: 'use strict';
  
  /**
   * explain_find.js
   *
   * Runs explain() and find() on a collection.
   *
   */
  load('jstests/concurrency/fsm_libs/extend_workload.js');  // for extendWorkload
  load('jstests/concurrency/fsm_workloads/explain.js');     // for $config
  load('jstests/libs/analyze_plan.js');                     // for planHasStage and isIxscan
  
  var $config = extendWorkload($config, function($config, $super) {
  
      $config.states = Object.extend({
          explainLimit: function explainLimit(db, collName) {
              var res = db[collName].find().limit(3).explain();
              assertAlways.commandWorked(res);
              assertAlways(planHasStage(res.queryPlanner.winningPlan, 'LIMIT'));
          },
          explainBatchSize: function explainBatchSize(db, collName) {
              var res = db[collName].find().batchSize(3).explain();
              assertAlways.commandWorked(res);
          },
          explainAddOption: function explainAddOption(db, collName) {
              var res = db[collName].explain().find().addOption(DBQuery.Option.exhaust).finish();
              assertAlways.commandWorked(res);
          },
          explainSkip: function explainSkip(db, collName) {
              var res = db[collName].explain().find().skip(3).finish();
              assertAlways.commandWorked(res);
              assertAlways(planHasStage(res.queryPlanner.winningPlan, 'SKIP'));
          },
          explainSort: function explainSort(db, collName) {
              var res = db[collName].find().sort({i: -1}).explain();
              assertAlways.commandWorked(res);
              assertAlways(planHasStage(res.queryPlanner.winningPlan, 'SORT'));
          },
          explainHint: function explainHint(db, collName) {
              assertWhenOwnColl(function() {
                  var res = db[collName].find().hint({j: 1}).explain();
                  assertWhenOwnColl.commandWorked(res);
                  assertWhenOwnColl(isIxscan(res.queryPlanner.winningPlan));
              });
          },
          explainMaxTimeMS: function explainMaxTimeMS(db, collName) {
              var res = db[collName].find().maxTimeMS(2000).explain();
              assertAlways.commandWorked(res);
          },
          explainSnapshot: function explainSnapshot(db, collName) {
              var res = db[collName].find().snapshot().explain();
              assertAlways.commandWorked(res);
              assertWhenOwnColl(isIxscan(res.queryPlanner.winningPlan));
          }
      },
                                     $super.states);
  
      $config.transitions = Object.extend(
          {explain: $config.data.assignEqualProbsToTransitions($config.states)}, $super.transitions);
  
      // doubling number of iterations so there is a higher chance we will
      // transition to each of the 8 new states at least once
      $config.iterations = $super.iterations * 2;
  
      return $config;
  });
  