1 files changed, 67 insertions, 0 deletions
diff --git a/jstests/concurrency/fsm_workloads/explain_update.js b/jstests/concurrency/fsm_workloads/explain_update.js
new file mode 100644
index 00000000000..f72f06babb5
--- /dev/null
+++ b/jstests/concurrency/fsm_workloads/explain_update.js
@@ -0,0 +1,67 @@
+'use strict';
+
+/**
+ * explain_update.js
+ *
+ * Runs explain() and update() on a collection.
+ */
+load('jstests/concurrency/fsm_libs/extend_workload.js'); // for extendWorkload
+load('jstests/concurrency/fsm_workloads/explain.js'); // for $config
+load('jstests/concurrency/fsm_workload_helpers/server_types.js'); // for isMongos
+
+var $config = extendWorkload($config, function($config, $super) {
+
+    $config.states = Object.extend({
+        explainBasicUpdate: function explainBasicUpdate(db, collName) {
+            var res = db[collName].explain('executionStats').update({i: this.nInserted},
+                                                                    {$set: {j: 49}});
+            assertAlways.commandWorked(res);
+            assertWhenOwnColl(function() {
+                assertWhenOwnColl.eq(1, explain.executionStats.totalDocsExamined);
+
+                // document should not have been updated.
+                var doc = db[collName].findOne({ i: this.nInserted });
+                assertWhenOwnColl.eq(2 * this.nInserted, doc.j);
+            }.bind(this));
+        },
+        explainUpdateUpsert: function explainUpdateUpsert(db, collName) {
+            var res = db[collName].explain('executionStats').update({i: 2 * this.nInserted + 1},
+                                                                    {$set: {j: 81}},
+                                                                    /* upsert */ true);
+            assertAlways.commandWorked(res);
+            var stage = res.executionStats.executionStages;
+
+            // if explaining a write command through mongos
+            if (isMongos(db)) {
+                stage = stage.shards[0].executionStages;
+            }
+            assertAlways.eq(stage.stage, 'UPDATE');
+            assertWhenOwnColl(stage.wouldInsert);
+
+            // make sure that the insert didn't actually happen.
+            assertWhenOwnColl.eq(this.nInserted, db[collName].find().itcount());
+        },
+        explainUpdateMulti: function explainUpdateMulti(db, collName) {
+            var res = db[collName].explain('executionStats').update({i: {$lte: 2}}, {$set: {b: 3}},
+                                                                     /* upsert */ false,
+                                                                     /* multi */ true);
+            assertAlways.commandWorked(res);
+            var stage = res.executionStats.executionStages;
+
+            // if explaining a write command through mongos
+            if (isMongos(db)) {
+                stage = stage.shards[0].executionStages;
+            }
+            assertAlways.eq(stage.stage, 'UPDATE');
+            assertWhenOwnColl(!stage.wouldInsert);
+            assertWhenOwnColl.eq(3, stage.nMatched);
+            assertWhenOwnColl.eq(3, stage.nWouldModify);
+        }
+    }, $super.states);
+
+    $config.transitions = Object.extend({
+        explain: $config.data.assignEqualProbsToTransitions($config.states)
+    }, $super.transitions);
+
+    return $config;
+});