diff --git a/test/Microsoft.AspNet.WebSockets.Protocol.Test/BufferStream.cs b/test/Microsoft.AspNet.WebSockets.Protocol.Test/BufferStream.cs
index f06f4889eb..9d49f8ec10 100644
--- a/test/Microsoft.AspNet.WebSockets.Protocol.Test/BufferStream.cs
+++ b/test/Microsoft.AspNet.WebSockets.Protocol.Test/BufferStream.cs
@@ -138,6 +138,7 @@ namespace Microsoft.AspNet.WebSockets.Protocol.Test
             }
         }
 
+#if !DNXCORE50
         public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
         {
             // TODO: This option doesn't preserve the state object.
@@ -197,6 +198,7 @@ namespace Microsoft.AspNet.WebSockets.Protocol.Test
                 _readLock.Release();
             }
         }
+#endif
 
         // Write with count 0 will still trigger OnFirstWrite
         public override void Write(byte[] buffer, int offset, int count)
@@ -224,6 +226,7 @@ namespace Microsoft.AspNet.WebSockets.Protocol.Test
             }
         }
 
+#if !DNXCORE50
         public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
         {
             Write(buffer, offset, count);
@@ -254,6 +257,7 @@ namespace Microsoft.AspNet.WebSockets.Protocol.Test
             Write(buffer, offset, count);
             return Task.FromResult<object>(null);
         }
+#endif
 
         private static void VerifyBuffer(byte[] buffer, int offset, int count, bool allowEmpty)
         {
diff --git a/test/Microsoft.AspNet.WebSockets.Protocol.Test/DuplexStream.cs b/test/Microsoft.AspNet.WebSockets.Protocol.Test/DuplexStream.cs
index 102ccbd0c3..09e87c660f 100644
--- a/test/Microsoft.AspNet.WebSockets.Protocol.Test/DuplexStream.cs
+++ b/test/Microsoft.AspNet.WebSockets.Protocol.Test/DuplexStream.cs
@@ -93,6 +93,7 @@ namespace Microsoft.AspNet.WebSockets.Protocol.Test
             return _readStream.Read(buffer, offset, count);
         }
 
+#if !DNXCORE50
         public override int ReadByte()
         {
             return _readStream.ReadByte();
@@ -117,6 +118,7 @@ namespace Microsoft.AspNet.WebSockets.Protocol.Test
         {
             return _readStream.CopyToAsync(destination, bufferSize, cancellationToken);
         }
+#endif
 
 #endregion Read
 
@@ -127,6 +129,7 @@ namespace Microsoft.AspNet.WebSockets.Protocol.Test
             _writeStream.Write(buffer, offset, count);
         }
 
+#if !DNXCORE50
         public override void WriteByte(byte value)
         {
             _writeStream.WriteByte(value);
@@ -147,15 +150,16 @@ namespace Microsoft.AspNet.WebSockets.Protocol.Test
             return _writeStream.WriteAsync(buffer, offset, count, cancellationToken);
         }
 
-        public override void Flush()
-        {
-            _writeStream.Flush();
-        }
-
         public override Task FlushAsync(CancellationToken cancellationToken)
         {
             return _writeStream.FlushAsync(cancellationToken);
         }
+#endif
+
+        public override void Flush()
+        {
+            _writeStream.Flush();
+        }
 
 #endregion Write
 
diff --git a/test/Microsoft.AspNet.WebSockets.Protocol.Test/project.json b/test/Microsoft.AspNet.WebSockets.Protocol.Test/project.json
index 182337015c..8b6e88160a 100644
--- a/test/Microsoft.AspNet.WebSockets.Protocol.Test/project.json
+++ b/test/Microsoft.AspNet.WebSockets.Protocol.Test/project.json
@@ -4,7 +4,10 @@
         "xunit.runner.aspnet": "2.0.0-aspnet-*"
     },
     "frameworks": {
-        "dnx451": { }
+        "dnx451": { },
+        "dnxcore50": {
+            "System.IO": "4.0.11-beta-*"
+        }
     },
     "commands": {
         "test": "xunit.runner.aspnet"