Addded language identifier tests.

JSMR.Infrastructure/Common/Languages/LanguageIdentifier.cs

@@ -26,6 +26,9 @@ public class LanguageIdentifier : ILanguageIdentifier
 
     public Language GetLanguage(string text)
     {
+        if (string.IsNullOrWhiteSpace(text))
+            return Language.Unknown;
+
         var rankedLanguages = _identifier.Identify(text).Where(x => _languages.Contains(x.Item1.Iso639_3));
         var identifiedLanguage = rankedLanguages.OrderBy(x => x.Item2).FirstOrDefault();