Fix findRandom when selector does not match any documents.

fehmicansaglam · Jul 15, 2014 · 3a4dab9 · 3a4dab9
1 parent a1fe9e4
commit 3a4dab9
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diff --git a/bson/src/main/scala/dao/BsonDao.scala b/bson/src/main/scala/dao/BsonDao.scala
@@ -156,7 +156,7 @@ abstract class BsonDao[Model, ID](db: () => DB, collectionName: String)(implicit
   def findRandom(selector: BSONDocument = BSONDocument.empty): Future[Option[Model]] = {
     for {
       count <- count(selector)
-      index = Random.nextInt(count)
+      index = if (count == 0) 0 else Random.nextInt(count)
       random <- collection.find(selector).options(QueryOpts(skipN = index, batchSizeN = 1)).one[Model]
     } yield random
   }

diff --git a/bson/src/test/scala/dao/DummyBsonDaoSpec.scala b/bson/src/test/scala/dao/DummyBsonDaoSpec.scala
@@ -121,6 +121,19 @@ class DummyBsonDaoSpec
     }
   }
 
+  it should "return None when findRandom does not match any documents" in {
+    val dummyModel = DummyModel(name = "foo", surname = "bar", age = 32)
+
+    val futureResult = for {
+      insertCount <- dao.insert(dummyModel)
+      random <- dao.findRandom("age" $gt 50 $lt 60)
+    } yield random
+
+    whenReady(futureResult) { random =>
+      random should be('empty)
+    }
+  }
+
   it should "find all of the selected documents" in {
     val dummyModels = DummyModel.random(100)