[feat] Add Response caching

Octokit.Tests/Helpers/StringKeyedDictionaryComparer.cs

@@ -0,0 +1,23 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Octokit.Tests.Helpers
+{
+    public class StringKeyedDictionaryComparer<T> : IEqualityComparer<IReadOnlyDictionary<string, T>>
+    {
+        public bool Equals(IReadOnlyDictionary<string, T> x, IReadOnlyDictionary<string, T> y)
+        {
+            if (ReferenceEquals(x, y)) return true;
+            if (ReferenceEquals(x, null)) return false;
+            if (ReferenceEquals(y, null)) return false;
+            if (x.GetType() != y.GetType()) return false;
+
+            return x.Count == y.Count && x.Intersect(y).Count() == x.Count;
+        }
+
+        public int GetHashCode(IReadOnlyDictionary<string, T> obj)
+        {
+            return obj.Count;
+        }
+    }
+}