* Fixed bug: invalid xml if property names contain space at begin or end anf first non space digit is not a letter or string begins with "xml" (example: " xmlName").

* Added unit tests for XmlPropertyFormatter.GetValidElementName()

Author: ckadluba

src/Serilog.Sinks.MSSqlServer/Sinks/MSSqlServer/Output/XmlPropertyFormatter.cs

@@ -180,7 +180,7 @@ public string GetValidElementName(string name)
 
             if (!char.IsLetter(validName[0]) || validName.StartsWith("xml", true, CultureInfo.CurrentCulture))
             {
-                validName = "x" + name;
+                validName = "x" + validName;
             }
 
             validName = Regex.Replace(validName, @"\s", "_");

test/Serilog.Sinks.MSSqlServer.Tests/Sinks/MSSqlServer/Output/XmlPropertyFormatterTests.cs

@@ -0,0 +1,82 @@
+using Serilog.Sinks.MSSqlServer.Output;
+using Xunit;
+
+namespace Serilog.Sinks.MSSqlServer.Tests.Sinks.MSSqlServer.Output
+{
+    public class XmlPropertyFormatterTests
+    {
+        [Fact]
+        public void GetValidElementNameReturnsValidNameOnNull()
+        {
+            var sut = new XmlPropertyFormatter();
+
+            var result = sut.GetValidElementName(null);
+
+            Assert.Equal("x", result);
+        }
+
+        [Fact]
+        public void GetValidElementNameReturnsValidNameOnEmpty()
+        {
+            var sut = new XmlPropertyFormatter();
+
+            var result = sut.GetValidElementName(string.Empty);
+
+            Assert.Equal("x", result);
+        }
+
+        [Fact]
+        public void GetValidElementNameTrimsWhitespace()
+        {
+            var sut = new XmlPropertyFormatter();
+
+            var result = sut.GetValidElementName("  \tname   \t");
+
+            Assert.Equal("name", result);
+        }
+
+        [Fact]
+        public void GetValidElementNamePrependsXIfNonLetterAtBegin()
+        {
+            var sut = new XmlPropertyFormatter();
+
+            var result = sut.GetValidElementName("$Name");
+
+            Assert.Equal("x$Name", result);
+        }
+
+        [Fact]
+        public void GetValidElementNamePrependsXIfXmlAtBeginCaseInsensitive()
+        {
+            var sut = new XmlPropertyFormatter();
+
+            var result = sut.GetValidElementName("xmlName");
+            Assert.Equal("xxmlName", result);
+
+            var result2 = sut.GetValidElementName("XmlName");
+            Assert.Equal("xXmlName", result2);
+        }
+
+        [Fact]
+        public void GetValidElementNameTrimsWhitespaceAndPrependsXIfInvalidBegin()
+        {
+            var sut = new XmlPropertyFormatter();
+
+            var result = sut.GetValidElementName(" xmlName ");
+            Assert.Equal("xxmlName", result);
+
+            var result2 = sut.GetValidElementName(" 4Name ");
+            Assert.Equal("x4Name", result2);
+        }
+
+        [Fact]
+        public void GetValidElementNameReplacesEnclosedWhitespaceWithUnderscore()
+        {
+            var sut = new XmlPropertyFormatter();
+
+            var result = sut.GetValidElementName("Name\tWith   Space");
+
+            Assert.Equal("Name_With___Space", result);
+        }
+    }
+}