distributed memoizer added to ensure absolute duplicate posts don't get through

in case of an absolute dupe just return the memoized post

This works around issues with wordpress being crazy

spec/components/distributed_memoizer_spec.rb

@@ -0,0 +1,55 @@
+require 'spec_helper'
+require_dependency 'distributed_memoizer'
+
+describe DistributedMemoizer do
+
+  before do
+    $redis.del(DistributedMemoizer.redis_key("hello"))
+    $redis.del(DistributedMemoizer.redis_lock_key("hello"))
+    $redis.unwatch
+  end
+
+  # NOTE we could use a mock redis here, but I think it makes sense to test the real thing
+  # let(:mock_redis) { MockRedis.new }
+
+  def memoize(&block)
+    DistributedMemoizer.memoize("hello", duration = 120, &block)
+  end
+
+  it "returns the value of a block" do
+    memoize do
+      "abc"
+    end.should == "abc"
+  end
+
+  it "return the old value once memoized" do
+
+    memoize do
+      "abc"
+    end
+
+    memoize do
+      "world"
+    end.should == "abc"
+  end
+
+  it "memoizes correctly when used concurrently" do
+    results = []
+    threads = []
+
+    5.times do
+      threads << Thread.new do
+        results << memoize do
+          sleep 0.001
+          SecureRandom.hex
+        end
+      end
+    end
+
+    threads.each(&:join)
+    results.uniq.length.should == 1
+    results.count.should == 5
+
+  end
+
+end