Add Proxy Setting for: SaveMappingForStatusCodePattern to only save the mapping when the status code matches the pattern (#357)

* proxy

* HttpStatusRangeParserTests

* test

src/WireMock.Net/Util/HttpStatusRangeParser.cs

@@ -0,0 +1,71 @@
+using System;
+using System.Linq;
+using System.Net;
+using System.Text.RegularExpressions;
+
+namespace WireMock.Util
+{
+    /// <summary>
+    /// Based on https://github.com/tmenier/Flurl/blob/129565361e135e639f1d44a35a78aea4302ac6ca/src/Flurl.Http/HttpStatusRangeParser.cs
+    /// </summary>
+    internal static class HttpStatusRangeParser
+    {
+        /// <summary>
+        /// Determines whether the specified pattern is match.
+        /// </summary>
+        /// <param name="pattern">The pattern. (Can be null, in that case it's allowed.)</param>
+        /// <param name="httpStatusCode">The value.</param>
+        /// <exception cref="ArgumentException"><paramref name="pattern"/> is invalid.</exception>
+        public static bool IsMatch(string pattern, HttpStatusCode httpStatusCode)
+        {
+            return IsMatch(pattern, (int)httpStatusCode);
+        }
+
+        /// <summary>
+        /// Determines whether the specified pattern is match.
+        /// </summary>
+        /// <param name="pattern">The pattern. (Can be null, in that case it's allowed.)</param>
+        /// <param name="httpStatusCode">The value.</param>
+        /// <exception cref="ArgumentException"><paramref name="pattern"/> is invalid.</exception>
+        public static bool IsMatch(string pattern, int httpStatusCode)
+        {
+            if (pattern == null)
+            {
+                return true;
+            }
+
+            foreach (var range in pattern.Split(',').Select(p => p.Trim()))
+            {
+                switch (range)
+                {
+                    case "":
+                        continue;
+
+                    case "*":
+                        return true; // special case - allow everything
+                }
+
+                string[] bounds = range.Split('-');
+                int lower = 0;
+                int upper = 0;
+
+                bool valid =
+                    bounds.Length <= 2 &&
+                    int.TryParse(Regex.Replace(bounds.First().Trim(), "[*xX]", "0"), out lower) &&
+                    int.TryParse(Regex.Replace(bounds.Last().Trim(), "[*xX]", "9"), out upper);
+
+                if (!valid)
+                {
+                    throw new ArgumentException($"Invalid range pattern: \"{pattern}\". Examples of allowed patterns: \"400\", \"4xx\", \"300,400-403\", \"*\".");
+                }
+
+                if (httpStatusCode >= lower && httpStatusCode <= upper)
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+    }
+}