Add SSL+Upgrade regression test

test/Microsoft.AspNet.Server.KestrelTests/StreamSocketOutputTests.cs

@@ -0,0 +1,106 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.IO;
+using Microsoft.AspNet.Server.Kestrel.Filter;
+using Microsoft.AspNet.Server.Kestrel.Http;
+using Xunit;
+
+namespace Microsoft.AspNet.Server.KestrelTests
+{
+    public class StreamSocketOutputTests
+    {
+        [Fact]
+        public void DoesNotThrowForNullBuffers()
+        {
+            // This test was added because SslStream throws if passed null buffers with (count == 0)
+            // Which happens if ProduceEnd is called in Frame without _responseStarted == true
+            // As it calls ProduceStart with write immediate == true
+            // This happens in WebSocket Upgrade over SSL
+
+            ISocketOutput socketOutput = new StreamSocketOutput(new ThrowsOnNullWriteStream(), null);
+
+            // Should not throw
+            socketOutput.Write(default(ArraySegment<byte>), true);
+
+            Assert.True(true);
+        }
+
+        private class ThrowsOnNullWriteStream : Stream
+        {
+            public override bool CanRead
+            {
+                get
+                {
+                    throw new NotImplementedException();
+                }
+            }
+
+            public override bool CanSeek
+            {
+                get
+                {
+                    throw new NotImplementedException();
+                }
+            }
+
+            public override bool CanWrite
+            {
+                get
+                {
+                    throw new NotImplementedException();
+                }
+            }
+
+            public override long Length
+            {
+                get
+                {
+                    throw new NotImplementedException();
+                }
+            }
+
+            public override long Position
+            {
+                get
+                {
+                    throw new NotImplementedException();
+                }
+
+                set
+                {
+                    throw new NotImplementedException();
+                }
+            }
+
+            public override void Flush()
+            {
+                throw new NotImplementedException();
+            }
+
+            public override int Read(byte[] buffer, int offset, int count)
+            {
+                throw new NotImplementedException();
+            }
+
+            public override long Seek(long offset, SeekOrigin origin)
+            {
+                throw new NotImplementedException();
+            }
+
+            public override void SetLength(long value)
+            {
+                throw new NotImplementedException();
+            }
+
+            public override void Write(byte[] buffer, int offset, int count)
+            {
+                if (buffer == null)
+                {
+                    throw new ArgumentNullException(nameof(buffer));
+                }
+            }
+        }
+    }
+}