Improve new Guid tests (#246)

***NO_CI***

Author: josesimoes

Tests/NFUnitTestSystemLib/UnitTestGuid.cs

@@ -419,15 +419,29 @@ public void Ctor_UInt_UShort_UShort_Byte_Byte_Byte_Byte_Byte_Byte_Byte_Byte()
         [TestMethod]
         public void NewGuid()
         {
+            // generate a new Guid
             Guid guid1 = Guid.NewGuid();
 
+            OutputHelper.WriteLine($"Guid1: {guid1}");
+
+            // check that the guid is not empty
             Assert.AreNotEqual(Guid.Empty, guid1);
+            // check version 4
             Assert.IsTrue((guid1.ToByteArray()[7] & 0xF0) == 0x40);
+            // check variant
+            Assert.IsTrue((guid1.ToByteArray()[8] & 0xC0) == 0x80);
 
+            // go for another one
             Guid guid2 = Guid.NewGuid();
 
+            OutputHelper.WriteLine($"Guid2: {guid2}");
+
+            // check that the guid is not empty
             Assert.AreNotEqual(guid1, guid2);
+            // check version 4
             Assert.IsTrue((guid2.ToByteArray()[7] & 0xF0) == 0x40);
+            // check variant
+            Assert.IsTrue((guid2.ToByteArray()[8] & 0xC0) == 0x80);
         }
 
         [TestMethod]