Align default newline with .NET (#84)

***NO_CI***

Author: networkfusion

README.md

@@ -93,12 +93,12 @@ You can as well write and read strings:
 ```csharp
 string toSend = "I ❤ nanoFramework";
 port.WriteLine(toSend);
-// this will send the string encoded finishing by a new line, by default \r\n
-// You can change the new line by anything:
+// this will send the string encoded finishing by a new line, by default `\n`
+// You can change the new line to be anything:
 port.NewLine = "❤❤";
-// Now it will send the 2 hearts as the end of line while operating a ReadLine or WriteLine
-// You can ad anytime change it back:
-port.NewLine = SerialPort.DefaultNewLine; // default is "\r\n"
+// Now it will send 2 hearts as the line ending `WriteLine` and will use 2 hearts as the terminator for `ReadLine`.
+// You can change it back to the `\n` default at anytime:
+port.NewLine = SerialPort.DefaultNewLine; // default is "\n"
 // This will read the existing buffer:
 string existingString = port.ReadExisting();
 // Note that if it can't properly convert the bytes to a string, you'll get an exception

System.IO.Ports/SerialPort.cs

@@ -15,7 +15,7 @@ public sealed class SerialPort : IDisposable
     {
         // default new line
         [System.Diagnostics.DebuggerBrowsable(Diagnostics.DebuggerBrowsableState.Never)]
-        private const string _defaultNewLine = "\r";
+        private const string _defaultNewLine = "\n";
 
         [System.Diagnostics.DebuggerBrowsable(Diagnostics.DebuggerBrowsableState.Never)]
         private static readonly SerialDeviceEventListener s_eventListener = new();

Tests/UnitTestsSerialPort/README.md

@@ -0,0 +1,5 @@
+# SerialPort Unit Tests
+Note:
+The current unit tests only run on real hardware, and are currently setup for ESP32 devices with `COM2` and `COM3` available and interconnected.
+Other devices can be added easily by changing the `SetupComPorts` in [SerialTests.cs](SerialTests.cs).
+

Tests/UnitTestsSerialPort/SerialTests.cs

@@ -93,6 +93,23 @@ public void BasicReadWriteTests()
             }
         }
 
+        [TestMethod]
+        public void VerifyDefaultReadLineCharacter()
+        {
+            // Arrange
+            EnsurePortsOpen();
+            _serOne.WriteTimeout = 1000;
+            _serOne.ReadTimeout = 1000;
+            _serTwo.WriteTimeout = 1000;
+            _serTwo.ReadTimeout = 1000;
+            string toSend = "This is a simple test for verifying the default readline character \r\n \\r";
+            // Act
+            _serOne.Write(toSend);
+            string toReceive = _serTwo.ReadLine();
+            // Assert
+            Assert.Equal(toSend, toReceive + "\\r" + _serOne.NewLine);
+        }
+
         [TestMethod]
         public void WriteAndReadStringTests()
         {