CSHARP-713: MongoDatabase.Eval doesn't send argument to server when there is exactly one argument.

Author: rstam

MongoDB.Driver/MongoDatabase.cs

@@ -378,7 +378,7 @@ public virtual CommandResult DropCollection(string collectionName)
         /// <returns>The result of evaluating the code.</returns>
         public virtual BsonValue Eval(EvalFlags flags, BsonJavaScript code, params object[] args)
         {
-            var argsArray = (args != null && args.Length > 1) ? new BsonArray(args) : null;
+            var argsArray = (args != null && args.Length > 0) ? new BsonArray(args) : null;
             var command = new CommandDocument
             {
                 { "$eval", code },

MongoDB.DriverUnitTests/MongoDatabaseTests.cs

@@ -99,15 +99,31 @@ public void TestEvalNoArgsNoLock()
         }
 
         [Test]
-        public void TestEvalWithArgs()
+        public void TestEvalWithOneArg()
+        {
+            var code = "function(x) { return x + 1; }";
+            var result = _database.Eval(code, 1);
+            Assert.AreEqual(2, result.ToInt32());
+        }
+
+        [Test]
+        public void TestEvalWithOneArgNoLock()
+        {
+            var code = "function(x) { return x + 1; }";
+            var result = _database.Eval(EvalFlags.NoLock, code, 1);
+            Assert.AreEqual(2, result.ToInt32());
+        }
+
+        [Test]
+        public void TestEvalWithTwoArgs()
         {
             var code = "function(x, y) { return x / y; }";
             var result = _database.Eval(code, 6, 2);
             Assert.AreEqual(3, result.ToInt32());
         }
 
         [Test]
-        public void TestEvalWithArgsNoLock()
+        public void TestEvalWithTwoArgsNoLock()
         {
             var code = "function(x, y) { return x / y; }";
             var result = _database.Eval(EvalFlags.NoLock, code, 6, 2);