[Test] Fix build of System.Core unit tests

diff --git a/mcs/class/System.Core/Test/System.Linq/EnumerableFixture.cs b/mcs/class/System.Core/Test/System.Linq/EnumerableFixture.cs
index 55d240df83c738b250a7d3b154f18444d9817574..1045c8521b986d35d351ff9f383b2f5763660d7d 100644 (file)
--- a/mcs/class/System.Core/Test/System.Linq/EnumerableFixture.cs
+++ b/mcs/class/System.Core/Test/System.Linq/EnumerableFixture.cs
@@ -28,6 +28,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Globalization;
 using System.Text;
 using System.Threading;