Only call hdel and after_unlike when like exists

lib/likeable.rb

@@ -43,10 +43,12 @@ def after_like(like)
 
   # removes a like
   def remove_like_from(user)
-    Likeable.redis.hdel(like_key, user.id)
-    Likeable.redis.hdel(user.like_key(self.class.to_s.downcase), self.id)
-    after_unlike(user)
-    clear_memoized_methods(:like_count, :like_user_ids, :liked_user_ids, :liked_users)
+    if Likeable.redis.hexists(like_key, user.id)
+      Likeable.redis.hdel(like_key, user.id)
+      Likeable.redis.hdel(user.like_key(self.class.to_s.downcase), self.id)
+      after_unlike(user)
+      clear_memoized_methods(:like_count, :like_user_ids, :liked_user_ids, :liked_users)
+    end
   end
 
   def after_unlike(user)

spec/likeable_spec.rb

@@ -43,11 +43,19 @@ def id
       it "removes a like" do
         target_class = @target.class.to_s.downcase
         user_like_key = "users:like:#{@user.id}:#{target_class}"
+        Likeable.redis.should_receive(:hexists).with("like_key", @user.id).and_return(true)
         @user.should_receive(:like_key).with(target_class).and_return(user_like_key)
         Likeable.redis.should_receive(:hdel).with("like_key", @user.id).once
         Likeable.redis.should_receive(:hdel).with(user_like_key, @target.id)
         @target.remove_like_from(@user)
       end
+
+      it "doesn't call after_unlike if like didn't exist" do
+        CleanTestClassForLikeable.after_unlike(:foo)
+        @target = CleanTestClassForLikeable.new
+        @target.should_not_receive(:foo)
+        @target.remove_like_from(@user)
+      end
     end
 
     describe "#liked_users" do
@@ -130,6 +138,7 @@ def id
       end
       it 'is called after a like is destroyed' do
         CleanTestClassForLikeable.after_unlike(:foo)
+        Likeable.redis.should_receive(:hexists).and_return(true)
         @target.should_receive(:foo)
         @target.remove_like_from(@user)
       end