Fixed: Now able to parse series names that use underscores instead of spaces

src/NzbDrone.Core.Test/ParserTests/ParserFixture.cs

@@ -80,6 +80,7 @@ namespace NzbDrone.Core.Test.ParserTests
         [TestCase("(Game of Thrones s03 e - \"Game of Thrones Season 3 Episode 10\"", "Game of Thrones", 3, 10)]
         [TestCase("House.Hunters.International.S05E607.720p.hdtv.x264", "House.Hunters.International", 5, 607)]
         [TestCase("Adventure.Time.With.Finn.And.Jake.S01E20.720p.BluRay.x264-DEiMOS", "Adventure.Time.With.Finn.And.Jake", 1, 20)]
+        [TestCase("Hostages.S01E04.2-45.PM.[HDTV-720p].mkv", "Hostages", 1, 4)]
         public void ParseTitle_single(string postTitle, string title, int seasonNumber, int episodeNumber)
         {
             var result = Parser.Parser.ParseTitle(postTitle);
@@ -230,6 +231,7 @@ namespace NzbDrone.Core.Test.ParserTests
         [TestCase("The.Daily.Show", "dailyshow")]
         [TestCase("Castle (2009)", "castle2009")]
         [TestCase("Parenthood.2010", "parenthood2010")]
+        [TestCase("Law_and_Order_SVU", "lawordersvu")]
         public void series_name_normalize(string parsedSeriesName, string seriesName)
         {
             var result = parsedSeriesName.CleanSeriesTitle();

src/NzbDrone.Core/Parser/Parser.cs

@@ -64,7 +64,7 @@ namespace NzbDrone.Core.Parser
                           RegexOptions.IgnoreCase | RegexOptions.Compiled)
             };
 
-        private static readonly Regex NormalizeRegex = new Regex(@"((^|\W)(a|an|the|and|or|of)($|\W|_))|\W|_|(?:(?<=[^0-9]+)|\b)(?!(?:19\d{2}|20\d{2}))\d+(?=[^0-9ip]+|\b)",
+        private static readonly Regex NormalizeRegex = new Regex(@"((^|\W|_)(a|an|the|and|or|of)($|\W|_))|\W|_|(?:(?<=[^0-9]+)|\b)(?!(?:19\d{2}|20\d{2}))\d+(?=[^0-9ip]+|\b)",
                                                                  RegexOptions.IgnoreCase | RegexOptions.Compiled);
 
         private static readonly Regex SimpleTitleRegex = new Regex(@"480[i|p]|720[i|p]|1080[i|p]|[x|h|x\s|h\s]264|DD\W?5\W1|\<|\>|\?|\*|\:|\|",