v4.0.0 (#1357)

Source/MQTTnet.Tests/MqttPacketWriter_Tests.cs

@@ -0,0 +1,34 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using MQTTnet.Formatter;
+
+namespace MQTTnet.Tests
+{
+    [TestClass]
+    public class MqttPacketWriter_Tests
+    {
+        protected virtual MqttBufferWriter WriterFactory()
+        {
+            return new MqttBufferWriter(4096, 65535);
+        }
+
+        [TestMethod]
+        public void WritePacket()
+        {
+            var writer = WriterFactory();
+            Assert.AreEqual(0, writer.Length);
+
+            writer.WriteString("1234567890");
+            Assert.AreEqual(10 + 2, writer.Length);
+
+            writer.WriteBinaryData(new byte[300]);
+            Assert.AreEqual(300 + 2 + 12, writer.Length);
+
+            writer.WriteBinaryData(new byte[5000]);
+            Assert.AreEqual(5000 + 2 + 300 + 2 + 12, writer.Length);
+        }
+    }
+}