Fix failing test

Author: melted-away

src/HtmlDiff/HtmlDiff.cs

@@ -30,11 +30,12 @@ public class HtmlDiff
             {"</sub>",0},
             {"</sup>",0},
             {"</strike>",0},
-            {"</s>",0}
+            {"</s>",0},
+            {"</span>", 0}
         };
 
         private static readonly Regex SpecialCaseOpeningTagRegex = new Regex(
-            "<((strong)|(b)|(i)|(em)|(big)|(small)|(u)|(sub)|(sup)|(strike)|(s))[\\>\\s]+", RegexOptions.Compiled | RegexOptions.IgnoreCase);
+            "<((strong)|(b)|(i)|(em)|(big)|(small)|(u)|(sub)|(sup)|(strike)|(s)|(span))[\\>\\s]+", RegexOptions.Compiled | RegexOptions.IgnoreCase);
 
 
         /// <summary>
@@ -268,7 +269,7 @@ private void InsertTag(string tag, string cssClass, List<string> words)
                         var openingTag = _specialTagDiffStack.Count == 0 ? null : _specialTagDiffStack.Pop();
 
                         // If we didn't have an opening tag, and we don't have a match with the previous tag used 
-                        if (openingTag == null || openingTag != words.Last().Replace("/", ""))
+                        if (openingTag == null || Utils.GetTagName(openingTag) != Utils.GetTagName(words.Last()))
                         {
                             // do nothing
                         }

src/HtmlDiff/Utils.cs

@@ -1,4 +1,5 @@
-using System.Linq;
+using System;
+using System.Linq;
 using System.Text.RegularExpressions;
 
 namespace HtmlDiff
@@ -10,6 +11,7 @@ public static class Utils
         private static Regex tagWordRegex = new Regex(@"<[^\s>]+", RegexOptions.Compiled);
         private static Regex whitespaceRegex = new Regex("^(\\s|&nbsp;)+$", RegexOptions.Compiled);
         private static Regex wordRegex = new Regex(@"[\w\#@]+", RegexOptions.Compiled | RegexOptions.ECMAScript);
+        private static Regex tagRegex = new Regex(@"\s*</?(?<name>[^\s>]+)[^>]*>\s*", RegexOptions.Compiled);
 
         private static readonly string[] SpecialCaseWordTags = { "<img" };
 
@@ -84,5 +86,16 @@ public static bool IsWord(char text)
         {
             return wordRegex.IsMatch(new string(new[] { text }));
         }
+
+        public static string GetTagName(string word)
+        {
+            var match = tagRegex.Match(word);
+
+            // returns empty string if it's not a tag
+            if (!match.Success)
+                return string.Empty;
+
+            return match.Groups["name"].Value.ToLower();
+        }
     }
 }