Added test websocket for unit testing

CryptoExchange.Net.UnitTests/TestImplementation.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
 using CryptoExchange.Net.Authentication;
 using CryptoExchange.Net.Interfaces;
 

CryptoExchange.Net/Implementation/TestWebsocket.cs

@@ -0,0 +1,68 @@
+using System;
+using System.Security.Authentication;
+using System.Threading;
+using System.Threading.Tasks;
+using CryptoExchange.Net.Interfaces;
+
+namespace CryptoExchange.Net.Implementation
+{
+    public class TestWebsocket: IWebsocket
+    {
+        public void Dispose()
+        {
+        }
+
+        public void SetEnabledSslProtocols(SslProtocols protocols)
+        {
+        }
+
+        public void SetProxy(string host, int port)
+        {
+        }
+
+        public event Action OnClose;
+        public event Action<string> OnMessage;
+        public event Action<Exception> OnError;
+        public event Action OnOpen;
+
+        public bool IsClosed { get; private set; }
+        public bool IsOpen { get; private set; }
+        public bool PingConnection { get; set; }
+        public TimeSpan PingInterval { get; set; }
+
+        public Task<bool> Connect()
+        {
+            IsClosed = false;
+            IsOpen = true;
+            OnOpen?.Invoke();
+
+            return Task.FromResult(true);
+        }
+
+        public void Send(string data)
+        {
+        }
+        
+        public void EnqueueMessage(string data)
+        {
+            Thread.Sleep(10);
+            OnMessage?.Invoke(data);
+        }
+
+        public void InvokeError(Exception ex, bool closeConnection)
+        {
+            Thread.Sleep(10);
+            OnError?.Invoke(ex);
+            if (closeConnection)
+                Close();
+        }
+
+        public Task Close()
+        {
+            IsClosed = true;
+            IsOpen = false;
+            OnClose?.Invoke();
+            return Task.FromResult(0);
+        }
+    }
+}

CryptoExchange.Net/Implementation/TestWebsocketFactory.cs

@@ -0,0 +1,13 @@
+using CryptoExchange.Net.Interfaces;
+using CryptoExchange.Net.Logging;
+
+namespace CryptoExchange.Net.Implementation
+{
+    public class TestWebsocketFactory : IWebsocketFactory
+    {
+        public IWebsocket CreateWebsocket(Log log, string url)
+        {
+            return new TestWebsocket();
+        }
+    }
+}