1 files changed, 91 insertions, 0 deletions
diff --git a/jstests/core/dbstats.js b/jstests/core/dbstats.js
new file mode 100644
index 00000000000..1547f06fd8a
--- /dev/null
+++ b/jstests/core/dbstats.js
@@ -0,0 +1,91 @@
+// Confirms that the dbStats command returns expected content.
+
+(function() {
+    "use strict";
+
+    function serverIsMongos() {
+        const res = db.runCommand("ismaster");
+        assert.commandWorked(res);
+        return res.msg === "isdbgrid";
+    }
+
+    const isMongoS = serverIsMongos();
+    const isMMAPv1 = jsTest.options().storageEngine === "mmapv1";
+
+    let testDB = db.getSiblingDB("dbstats_js");
+    assert.commandWorked(testDB.dropDatabase());
+
+    let coll = testDB["testColl"];
+    assert.commandWorked(coll.createIndex({x: 1}));
+    const doc = {_id: 1, x: 1};
+    assert.writeOK(coll.insert(doc));
+
+    let dbStats = testDB.runCommand({dbStats: 1});
+    assert.commandWorked(dbStats);
+
+    if (isMMAPv1) {
+        if (isMongoS) {
+            // When this test is run against mongoS with the mmapV1 storage engine the 'objects' and
+            // 'indexes' counts will vary depending on whether 'testColl' is sharded and on the # of
+            // shards (due to inclusion of system.indexes & system.namespaces counts).
+            assert(dbStats.hasOwnProperty("objects"), tojson(dbStats));
+            assert(dbStats.hasOwnProperty("indexes"), tojson(dbStats));
+        } else {
+            assert.eq(7,
+                      dbStats.objects,
+                      tojson(dbStats));  // Includes testColl, system.indexes & system.namespaces
+            assert.eq(2, dbStats.indexes, tojson(dbStats));
+        }
+        // 'dataSize' and 'avgObjSize' include document padding space under MMAPv1.
+        assert(dbStats.hasOwnProperty("dataSize"), tojson(dbStats));
+        assert(dbStats.hasOwnProperty("avgObjSize"), tojson(dbStats));
+    } else {
+        assert.eq(1, dbStats.objects, tojson(dbStats));  // Includes testColl only
+        const dataSize = Object.bsonsize(doc);
+        assert.eq(dataSize, dbStats.avgObjSize, tojson(dbStats));
+        assert.eq(dataSize, dbStats.dataSize, tojson(dbStats));
+
+        // Index count will vary on mongoS if an additional index is needed to support sharding.
+        if (isMongoS) {
+            assert(dbStats.hasOwnProperty("indexes"), tojson(dbStats));
+        } else {
+            assert.eq(2, dbStats.indexes, tojson(dbStats));
+        }
+    }
+
+    assert(dbStats.hasOwnProperty("storageSize"), tojson(dbStats));
+    assert(dbStats.hasOwnProperty("numExtents"), tojson(dbStats));
+    assert(dbStats.hasOwnProperty("indexSize"), tojson(dbStats));
+
+    // Confirm extentFreeList field existence. Displayed for mongoD running MMAPv1 and for mongoS
+    // regardless of storage engine.
+    if (isMMAPv1 || isMongoS) {
+        assert(dbStats.hasOwnProperty("extentFreeList"), tojson(dbStats));
+        assert(dbStats.extentFreeList.hasOwnProperty("num"), tojson(dbStats));
+        assert(dbStats.extentFreeList.hasOwnProperty("totalSize"), tojson(dbStats));
+    }
+
+    // Confirm collection and view counts on mongoD
+    if (!isMongoS) {
+        assert.eq(testDB.getName(), dbStats.db, tojson(dbStats));
+
+        // We wait to add a view until this point as it allows more exact testing of avgObjSize for
+        // WiredTiger above. Having more than 1 document would require floating point comparison.
+        assert.commandWorked(testDB.createView("testView", "testColl", []));
+
+        dbStats = testDB.runCommand({dbStats: 1});
+        assert.commandWorked(dbStats);
+
+        if (isMMAPv1) {
+            assert.eq(
+                4,
+                dbStats.collections,
+                tojson(dbStats));  // testColl + system.views + system.indexes + system.namespaces
+        } else {
+            assert.eq(2, dbStats.collections, tojson(dbStats));  // testColl + system.views
+        }
+
+        assert.eq(1, dbStats.views, tojson(dbStats));
+    }
+
+})();