resolve NRE in ToPascalCase

Author: mythz

src/ServiceStack.Text/StringExtensions.cs

@@ -705,7 +705,8 @@ public static string StripMarkdownMarkup(this string markdown)
         private const int LowerCaseOffset = 'a' - 'A';
         public static string ToCamelCase(this string value)
         {
-            if (String.IsNullOrEmpty(value)) return value;
+            if (string.IsNullOrEmpty(value)) 
+                return value;
 
             var len = value.Length;
             var newValue = new char[len];
@@ -731,14 +732,17 @@ public static string ToCamelCase(this string value)
 
         public static string ToPascalCase(this string value)
         {
-            if (String.IsNullOrEmpty(value)) return value;
+            if (string.IsNullOrEmpty(value)) 
+                return value;
 
             if (value.IndexOf('_') >= 0)
             {
                 var parts = value.Split('_');
                 var sb = StringBuilderThreadStatic.Allocate();
                 foreach (var part in parts)
                 {
+                    if (string.IsNullOrEmpty(part))
+                        continue;
                     var str = part.ToCamelCase();
                     sb.Append(char.ToUpper(str[0]) + str.SafeSubstring(1, str.Length));
                 }

tests/ServiceStack.Text.Tests/StringExtensionsTests.cs

@@ -237,6 +237,7 @@ public void Can_ToCamelCase_String()
             Assert.That("lllUlllUlll".ToCamelCase(), Is.EqualTo("lllUlllUlll"));
             Assert.That("".ToCamelCase(), Is.EqualTo(""));
             Assert.That(((string)null).ToCamelCase(), Is.EqualTo((string)null));
+            Assert.That("__type".ToCamelCase(), Is.EqualTo("__type"));
         }
 
         [Test]
@@ -343,6 +344,7 @@ public void Can_convert_ToPascalCase()
             Assert.That("aa_bb".ToPascalCase(), Is.EqualTo("AaBb"));
             Assert.That("Aa_Bb".ToPascalCase(), Is.EqualTo("AaBb"));
             Assert.That("AA_BB".ToPascalCase(), Is.EqualTo("AaBb"));
+            Assert.That("__type".ToPascalCase(), Is.EqualTo("Type"));
         }
 
         [Test]