PERF: Cache About#stats.

spec/support/shared_examples_for_stats_cacheable.rb

@@ -0,0 +1,23 @@
+shared_examples_for 'stats cachable' do
+  describe 'fetch_cached_stats' do
+    it 'returns the cached stats' do
+      begin
+        stats = { "visits" => 10 }
+        $redis.set(described_class.stats_cache_key, stats.to_json)
+        expect(described_class.fetch_cached_stats).to eq(stats)
+      ensure
+        $redis.del(described_class.stats_cache_key)
+      end
+    end
+
+    it 'returns nil if no stats has been cached' do
+      expect(described_class.fetch_cached_stats).to eq(nil)
+    end
+  end
+
+  describe 'fetch_stats' do
+    it 'has been implemented' do
+      expect{ described_class.fetch_stats }.to_not raise_error
+    end
+  end
+end