diff --git a/.gitignore b/.gitignore
index 31fda99..f4ed9a8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,4 @@
 Gemfile.lock
-/test_app/db/migrate/20*
 /test_app/db/schema.rb
 /pkg
+*~
diff --git a/README.md b/README.md
index 743c7ef..22333b9 100644
--- a/README.md
+++ b/README.md
@@ -120,6 +120,25 @@ If you'd like to include only unique impressions in your count:
 
   is_impressionable :counter_cache => { :column_name => :my_column, :unique => true }
 
+
+What if I only want to record unique impressions?
+-------------------------------------------------
+Maybe you only care about unique impressions and would like to eliminate unnecessary database calls. You can specify conditions for recording impressions in your controller:
+
+  # only record impression if the request has a unique combination of type, id, and session
+  impressionist :unique => [:impressionable_type, :impressionable_id, :session_hash]
+
+  # only record impression if the request has a unique combination of controller, action, and session
+  impressionist :unique => [:controller_name, :action_name, :session_hash]
+
+  # only record impression if session is unique
+  impressionist :unique => [:session_hash]
+
+Or you can use the `impressionist` method directly:
+
+  impressionist(impressionable, "some message", :unique => [:session_hash])
+
+
 Development Roadmap
 -------------------
 * Automatic impression logging in views.  For example, log initial view, and any partials called from initial view
diff --git a/app/controllers/impressionist_controller.rb b/app/controllers/impressionist_controller.rb
index c7be098..1b74eb2 100644
--- a/app/controllers/impressionist_controller.rb
+++ b/app/controllers/impressionist_controller.rb
@@ -3,27 +3,23 @@ require 'digest/sha2'
 module ImpressionistController
   module ClassMethods
     def impressionist(opts={})
-      before_filter { |c| c.impressionist_subapp_filter opts[:actions] }
+      before_filter { |c| c.impressionist_subapp_filter(opts[:actions], opts[:unique])}
     end
   end
-  
+
   module InstanceMethods
     def self.included(base)
       base.before_filter :impressionist_app_filter
     end
 
-    def impressionist(obj,message=nil)
+    def impressionist(obj,message=nil,opts={})
       unless bypass
         if obj.respond_to?("impressionable?")
-          obj.impressions.create(:message=> message,
-                                 :request_hash=> @impressionist_hash,
-                                 :session_hash=> request.session_options[:id],
-                                 :ip_address=> request.remote_ip,
-                                 :user_id=> user_id,
-                                 :controller_name=>controller_name,
-                                 :action_name=> action_name,
-                                 :referrer=>request.referer)
+          if unique_instance?(obj, opts[:unique])
+            obj.impressions.create(associative_create_statement({:message => message}))
+          end
         else
+          # we could create an impression anyway. for classes, too. why not?
           raise "#{obj.class.to_s} is not impressionable!"
         end
       end
@@ -33,31 +29,73 @@ module ImpressionistController
       @impressionist_hash = Digest::SHA2.hexdigest(Time.now.to_f.to_s+rand(10000).to_s)
     end
 
-    def impressionist_subapp_filter(actions=nil)
+    def impressionist_subapp_filter(actions=nil,unique_opts=nil)
       unless bypass
         actions.collect!{|a|a.to_s} unless actions.blank?
-        if actions.blank? or actions.include?(action_name)
-          Impression.create(:controller_name=> controller_name,
-                            :action_name=> action_name,
-                            :user_id=> user_id,
-                            :request_hash=> @impressionist_hash,
-                            :session_hash=> request.session_options[:id],
-                            :ip_address=> request.remote_ip,
-                            :impressionable_type=> controller_name.singularize.camelize,
-                            :impressionable_id=> params[:id],
-                            :referrer=>request.referer)
+        if (actions.blank? || actions.include?(action_name)) && unique?(unique_opts)
+          Impression.create(direct_create_statement)
         end
       end
     end
 
     private
+    
     def bypass
       Impressionist::Bots::WILD_CARDS.each do |wild_card|
         return true if request.user_agent and request.user_agent.downcase.include? wild_card
       end
       Impressionist::Bots::LIST.include? request.user_agent
     end
-
+    
+    def unique_instance?(impressionable, unique_opts)
+      return unique_opts.blank? || impressionable.impressions.where(unique_query(unique_opts)).size == 0
+    end
+    
+    def unique?(unique_opts)
+      return unique_opts.blank? || Impression.where(unique_query(unique_opts)).size == 0
+    end
+    
+    # creates the query to check for uniqueness
+    def unique_query(unique_opts)
+      full_statement = direct_create_statement
+      # reduce the full statement to the params we need for the specified unique options
+      unique_opts.reduce({}) do |query, param|
+        query[param] = full_statement[param]
+        query
+      end
+    end
+    
+    # creates a statment hash that contains default values for creating an impression via an AR relation.
+    def associative_create_statement(query_params={})
+      query_params.reverse_merge!(
+        :controller_name => controller_name,
+        :action_name => action_name,
+        :user_id => user_id,
+        :request_hash => @impressionist_hash,
+        :session_hash => session_hash,
+        :ip_address => request.remote_ip,
+        :referrer => request.referer
+        )
+    end
+    
+    # creates a statment hash that contains default values for creating an impression.
+    def direct_create_statement(query_params={})
+      query_params.reverse_merge!(
+        :impressionable_type => controller_name.singularize.camelize,
+        :impressionable_id=> params[:id]
+        )
+      associative_create_statement(query_params)
+    end
+    
+    def session_hash
+      # # careful: request.session_options[:id] encoding in rspec test was ASCII-8BIT
+      # # that broke the database query for uniqueness. not sure if this is a testing only issue.
+      # str = request.session_options[:id]
+      # logger.debug "Encoding: #{str.encoding.inspect}"
+      # # request.session_options[:id].encode("ISO-8859-1")
+      request.session_options[:id]
+    end
+    
     #use both @current_user and current_user helper
     def user_id
       user_id = @current_user ? @current_user.id : nil rescue nil
diff --git a/test_app/Gemfile b/test_app/Gemfile
index b69c41b..9bdd5db 100644
--- a/test_app/Gemfile
+++ b/test_app/Gemfile
@@ -3,7 +3,7 @@ source 'http://rubygems.org'
 gem 'rails', '3.1'
 gem 'sqlite3-ruby', :require => 'sqlite3'
 gem 'impressionist', :path=>"#{File.dirname(__FILE__)}/../"
-gem "pg"
+#gem "pg"
 
 group :development do
   gem 'ZenTest'
diff --git a/test_app/Gemfile.lock b/test_app/Gemfile.lock
index 24b0d29..5c4af6e 100644
--- a/test_app/Gemfile.lock
+++ b/test_app/Gemfile.lock
@@ -1,5 +1,5 @@
 PATH
-  remote: /Users/coryschires/Desktop/work/applications/impressionist
+  remote: /Users/coryschires/Desktop/impressionist
   specs:
     impressionist (0.4.0)
 
@@ -45,7 +45,7 @@ GEM
     autotest-standalone (4.5.8)
     bcrypt-ruby (3.0.1)
     builder (3.0.0)
-    capybara (1.1.1)
+    capybara (1.1.2)
       mime-types (>= 1.16)
       nokogiri (>= 1.3.3)
       rack (>= 1.0.0)
@@ -54,23 +54,23 @@ GEM
       xpath (~> 0.1.4)
     childprocess (0.2.2)
       ffi (~> 1.0.6)
-    cucumber (1.1.0)
+    cucumber (1.1.3)
       builder (>= 2.1.2)
       diff-lcs (>= 1.1.2)
-      gherkin (~> 2.5.0)
+      gherkin (~> 2.6.7)
       json (>= 1.4.6)
       term-ansicolor (>= 1.0.6)
-    cucumber-rails (1.1.1)
+    cucumber-rails (1.2.0)
       capybara (>= 1.1.1)
-      cucumber (>= 1.1.0)
+      cucumber (>= 1.1.1)
       nokogiri (>= 1.5.0)
     daemons (1.0.10)
-    database_cleaner (0.6.7)
+    database_cleaner (0.7.0)
     diff-lcs (1.1.3)
     erubis (2.7.0)
-    ffi (1.0.9)
+    ffi (1.0.11)
     gem_plugin (0.2.3)
-    gherkin (2.5.4)
+    gherkin (2.6.8)
       json (>= 1.4.6)
     hike (1.2.1)
     i18n (0.6.0)
@@ -88,8 +88,7 @@ GEM
       gem_plugin (~> 0.2.3)
     multi_json (1.0.3)
     nokogiri (1.5.0)
-    pg (0.11.0)
-    polyglot (0.3.2)
+    polyglot (0.3.3)
     rack (1.3.5)
     rack-cache (1.0.3)
       rack (>= 0.4)
@@ -130,28 +129,28 @@ GEM
       activesupport (~> 3.0)
       railties (~> 3.0)
       rspec (~> 2.7.0)
-    rubyzip (0.9.4)
-    selenium-webdriver (2.10.0)
+    rubyzip (0.9.5)
+    selenium-webdriver (2.13.0)
       childprocess (>= 0.2.1)
-      ffi (= 1.0.9)
+      ffi (~> 1.0.9)
       json_pure
       rubyzip
     spork (0.8.5)
     sprockets (2.0.3)
       hike (~> 1.2)
       rack (~> 1.0)
-      tilt (!= 1.3.0, ~> 1.1)
+      tilt (~> 1.1, != 1.3.0)
     sqlite3 (1.3.4)
     sqlite3-ruby (1.3.3)
       sqlite3 (>= 1.3.3)
-    systemu (2.4.0)
+    systemu (2.4.1)
     term-ansicolor (1.0.7)
     thor (0.14.6)
     tilt (1.3.3)
     treetop (1.4.10)
       polyglot
       polyglot (>= 0.3.1)
-    tzinfo (0.3.30)
+    tzinfo (0.3.31)
     xpath (0.1.4)
       nokogiri (~> 1.3)
 
@@ -169,7 +168,6 @@ DEPENDENCIES
   impressionist!
   launchy
   mongrel (= 1.2.0.pre2)
-  pg
   rails (= 3.1)
   rspec
   rspec-rails
diff --git a/test_app/app/controllers/dummy_controller.rb b/test_app/app/controllers/dummy_controller.rb
new file mode 100644
index 0000000..86664a6
--- /dev/null
+++ b/test_app/app/controllers/dummy_controller.rb
@@ -0,0 +1,6 @@
+# This controller imports the impressionist module to make the modules methods available for testing
+class DummyController < ActionController::Base
+
+  impressionist
+
+end
diff --git a/test_app/app/controllers/widgets_controller.rb b/test_app/app/controllers/widgets_controller.rb
index 880ba5a..3a7c5dd 100644
--- a/test_app/app/controllers/widgets_controller.rb
+++ b/test_app/app/controllers/widgets_controller.rb
@@ -1,5 +1,6 @@
 class WidgetsController < ApplicationController
-  impressionist :actions=>[:show,:index]
+  impressionist :actions=>[:show,:index], :unique => [:controller_name,:action_name,:impressionable_id]
+  
   def show
   end
   
@@ -8,4 +9,5 @@ class WidgetsController < ApplicationController
   
   def new
   end
+  
 end
\ No newline at end of file
diff --git a/test_app/app/models/dummy.rb b/test_app/app/models/dummy.rb
new file mode 100644
index 0000000..ebce846
--- /dev/null
+++ b/test_app/app/models/dummy.rb
@@ -0,0 +1,7 @@
+# We don't really care about this model. It's just being used to test the uniqueness controller
+# specs. Nevertheless, we need a model because the counter caching functionality expects it.
+#
+class Dummy < ActiveRecord::Base
+  self.abstract_class = true # doesn't need to be backed by an actual table
+  is_impressionable
+end
\ No newline at end of file
diff --git a/test_app/config/database.yml b/test_app/config/database.yml
index bccd3e9..077168a 100644
--- a/test_app/config/database.yml
+++ b/test_app/config/database.yml
@@ -6,28 +6,19 @@ development:
   pool: 5
   timeout: 5000
 
-# Warning: The database defined as "test" will be erased and
-# re-generated from your development database when you run "rake".
-# Do not set this db to the same as development or production.
-#test: &test
-#  adapter: sqlite3
-#  database: db/test.sqlite3
-#  pool: 5
-#  timeout: 5000
-
-test:
+test: &test
   adapter: sqlite3
   database: db/test.sqlite3
   pool: 5
   timeout: 5000
 
-pg_test:
-  adapter: postgresql
-  database: impressionist_test
-  username: johnmcaliley
-  password: 
-  host: localhost
-  encoding: UTF8
+#pg_test:
+#  adapter: postgresql
+#  database: impressionist_test
+#  username: johnmcaliley
+# password: 
+#  host: localhost
+#  encoding: UTF8
 
 production:
   adapter: sqlite3
diff --git a/test_app/db/migrate/20111127184039_create_widgets.rb b/test_app/db/migrate/20111127184039_create_widgets.rb
new file mode 100644
index 0000000..5cb1fe2
--- /dev/null
+++ b/test_app/db/migrate/20111127184039_create_widgets.rb
@@ -0,0 +1,15 @@
+class CreateWidgets < ActiveRecord::Migration
+  def self.up
+    create_table :widgets do |t|
+      t.string :name
+      t.integer :impressions_count
+
+      t.timestamps
+    end
+  end
+
+  def self.down
+    drop_table :widgets
+  end
+end
+
diff --git a/test_app/db/migrate/20111127193841_create_impressions_table.rb b/test_app/db/migrate/20111127193841_create_impressions_table.rb
new file mode 100644
index 0000000..22b6a90
--- /dev/null
+++ b/test_app/db/migrate/20111127193841_create_impressions_table.rb
@@ -0,0 +1,37 @@
+class CreateImpressionsTable < ActiveRecord::Migration
+  def self.up
+    create_table :impressions, :force => true do |t|
+      t.string :impressionable_type
+      t.integer :impressionable_id
+      t.integer :user_id
+      t.string :controller_name
+      t.string :action_name
+      t.string :view_name
+      t.string :request_hash
+      t.string :session_hash
+      t.string :ip_address
+      t.string :message
+      t.string :referrer
+      t.timestamps
+    end
+    add_index :impressions, [:impressionable_type, :impressionable_id, :request_hash], :name => "poly_request_index", :unique => false
+    add_index :impressions, [:impressionable_type, :impressionable_id, :ip_address], :name => "poly_ip_index", :unique => false
+    add_index :impressions, [:impressionable_type, :impressionable_id, :session_hash], :name => "poly_session_index", :unique => false    
+    add_index :impressions, [:controller_name,:action_name,:request_hash], :name => "controlleraction_request_index", :unique => false
+    add_index :impressions, [:controller_name,:action_name,:ip_address], :name => "controlleraction_ip_index", :unique => false
+    add_index :impressions, [:controller_name,:action_name,:session_hash], :name => "controlleraction_session_index", :unique => false        
+    add_index :impressions, :user_id
+  end
+
+  def self.down
+    remove_index :impressions, :name => :poly_request_index
+    remove_index :impressions, :name => :poly_ip_index
+    remove_index :impressions, :name => :poly_session_index        
+    remove_index :impressions, :name => :controlleraction_request_index
+    remove_index :impressions, :name => :controlleraction_ip_index
+    remove_index :impressions, :name => :controlleraction_session_index        
+    remove_index :impressions, :user_id
+    
+    drop_table :impressions
+  end
+end
\ No newline at end of file
diff --git a/test_app/spec/controllers/controller_spec.rb b/test_app/spec/controllers/controller_spec.rb
index 8f7fe09..5b35182 100644
--- a/test_app/spec/controllers/controller_spec.rb
+++ b/test_app/spec/controllers/controller_spec.rb
@@ -95,4 +95,31 @@ describe WidgetsController do
     get "show", :id=> 1
     Impression.all.size.should eq 11
   end
+  
+  describe "impressionist unique options" do
+    
+    it "should log unique impressions at the per action level" do
+      get "show", :id=> 1
+      Impression.all.size.should eq 12
+      get "show", :id=> 2
+      Impression.all.size.should eq 13
+      get "show", :id => 2
+      Impression.all.size.should eq 13
+      get "index"
+      Impression.all.size.should eq 14
+    end
+    
+    it "should log unique impressions only once per id" do
+      get "show", :id=> 1
+      Impression.all.size.should eq 12
+      get "show", :id=> 2
+      Impression.all.size.should eq 13
+      get "show", :id => 2
+      Impression.all.size.should eq 13
+      get "index"
+      Impression.all.size.should eq 14
+    end
+  
+  end
+  
 end
diff --git a/test_app/spec/controllers/impressionist_uniqueness_spec.rb b/test_app/spec/controllers/impressionist_uniqueness_spec.rb
new file mode 100644
index 0000000..74c2854
--- /dev/null
+++ b/test_app/spec/controllers/impressionist_uniqueness_spec.rb
@@ -0,0 +1,312 @@
+require "spec_helper.rb"
+
+# we use the posts controller as it uses the impressionsist module. any such controller would do.
+describe DummyController do
+
+  before do
+    @impression_count = Impression.all.size
+  end
+
+  describe "impressionist filter uniqueness" do
+
+    it "should ignore uniqueness if not requested" do
+      controller.impressionist_subapp_filter(nil, nil)
+      controller.impressionist_subapp_filter(nil, nil)
+      Impression.should have(@impression_count + 2).records
+    end
+
+    it "should recognize unique session" do
+      # the following line was necessary as session hash returned a binary string (ASCII-8BIT encoded)
+      controller.stub!(:session_hash).and_return(request.session_options[:id].encode("ISO-8859-1"))
+      controller.impressionist_subapp_filter(nil, [:session_hash])
+      controller.impressionist_subapp_filter(nil, [:session_hash])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize unique ip" do
+      controller.request.stub!(:remote_ip).and_return("1.2.3.4")
+      controller.impressionist_subapp_filter(nil, [:ip_address])
+      controller.impressionist_subapp_filter(nil, [:ip_address])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize unique request" do
+      controller.impressionist_subapp_filter(nil, [:request_hash])
+      controller.impressionist_subapp_filter(nil, [:request_hash])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize unique action" do
+      controller.stub!(:action_name).and_return("test_action")
+      controller.impressionist_subapp_filter(nil, [:action_name])
+      controller.impressionist_subapp_filter(nil, [:action_name])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize unique controller" do
+      controller.stub!(:controller_name).and_return("post")
+      controller.impressionist_subapp_filter(nil, [:controller_name])
+      controller.impressionist_subapp_filter(nil, [:controller_name])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize unique user" do
+      controller.stub!(:user_id).and_return(42)
+      controller.impressionist_subapp_filter(nil, [:user_id])
+      controller.impressionist_subapp_filter(nil, [:user_id])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize unique referer" do
+      controller.request.stub!(:referer).and_return("http://foo/bar")
+      controller.impressionist_subapp_filter(nil, [:referrer])
+      controller.impressionist_subapp_filter(nil, [:referrer])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize unique id" do
+      controller.stub!(:params).and_return({:id => "666"}) # for correct impressionable id in filter
+      controller.impressionist_subapp_filter(nil, [:impressionable_id])
+      controller.impressionist_subapp_filter(nil, [:impressionable_id])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    # extra redundant test for important controller and action combination.
+    it "should recognize different controller and action" do
+      controller.stub!(:controller_name).and_return("post")
+      controller.stub!(:action_name).and_return("test_action")
+      controller.impressionist_subapp_filter(nil, [:controller_name, :action_name])
+      controller.impressionist_subapp_filter(nil, [:controller_name, :action_name])
+      Impression.should have(@impression_count + 1).records
+      controller.stub!(:action_name).and_return("another_action")
+      controller.impressionist_subapp_filter(nil, [:controller_name, :action_name])
+      controller.impressionist_subapp_filter(nil, [:controller_name, :action_name])
+      Impression.should have(@impression_count + 2).records
+      controller.stub!(:controller_name).and_return("article")
+      controller.impressionist_subapp_filter(nil, [:controller_name, :action_name])
+      controller.impressionist_subapp_filter(nil, [:controller_name, :action_name])
+      Impression.should have(@impression_count + 3).records
+    end
+
+    it "should recognize different action" do
+      controller.stub!(:action_name).and_return("test_action")
+      controller.impressionist_subapp_filter(nil, [:action_name])
+      controller.impressionist_subapp_filter(nil, [:action_name])
+      Impression.should have(@impression_count + 1).records
+      controller.stub!(:action_name).and_return("another_action")
+      controller.impressionist_subapp_filter(nil, [:action_name])
+      controller.impressionist_subapp_filter(nil, [:action_name])
+      Impression.should have(@impression_count + 2).records
+    end
+
+    it "should recognize different controller" do
+      controller.stub!(:controller_name).and_return("post")
+      controller.impressionist_subapp_filter(nil, [:controller_name])
+      controller.impressionist_subapp_filter(nil, [:controller_name])
+      Impression.should have(@impression_count + 1).records
+      controller.stub!(:controller_name).and_return("article")
+      controller.impressionist_subapp_filter(nil, [:controller_name])
+      controller.impressionist_subapp_filter(nil, [:controller_name])
+      Impression.should have(@impression_count + 2).records
+    end
+
+    it "should recognize different session" do
+      controller.stub!(:session_hash).and_return("foo")
+      controller.impressionist_subapp_filter(nil, [:session_hash])
+      controller.impressionist_subapp_filter(nil, [:session_hash])
+      Impression.should have(@impression_count + 1).records
+      controller.stub!(:session_hash).and_return("bar")
+      controller.impressionist_subapp_filter(nil, [:session_hash])
+      controller.impressionist_subapp_filter(nil, [:session_hash])
+      Impression.should have(@impression_count + 2).records
+    end
+
+    it "should recognize different ip" do
+      controller.request.stub!(:remote_ip).and_return("1.2.3.4")
+      controller.impressionist_subapp_filter(nil, [:ip_address])
+      controller.impressionist_subapp_filter(nil, [:ip_address])
+      Impression.should have(@impression_count + 1).records
+      controller.request.stub!(:remote_ip).and_return("5.6.7.8")
+      controller.impressionist_subapp_filter(nil, [:ip_address])
+      controller.impressionist_subapp_filter(nil, [:ip_address])
+      Impression.should have(@impression_count + 2).records
+    end
+
+    it "should recognize different referer" do
+      controller.request.stub!(:referer).and_return("http://foo/bar")
+      controller.impressionist_subapp_filter(nil, [:referrer])
+      controller.impressionist_subapp_filter(nil, [:referrer])
+      Impression.should have(@impression_count + 1).records
+      controller.request.stub!(:referer).and_return("http://bar/fo")
+      controller.impressionist_subapp_filter(nil, [:referrer])
+      controller.impressionist_subapp_filter(nil, [:referrer])
+      Impression.should have(@impression_count + 2).records
+    end
+
+    it "should recognize different id" do
+      controller.stub!(:params).and_return({:id => "666"}) # for correct impressionable id in filter
+      controller.impressionist_subapp_filter(nil, [:impressionable_type, :impressionable_id])
+      controller.impressionist_subapp_filter(nil, [:impressionable_type, :impressionable_id])
+      controller.stub!(:params).and_return({:id => "42"}) # for correct impressionable id in filter
+      controller.impressionist_subapp_filter(nil, [:impressionable_type, :impressionable_id])
+      controller.impressionist_subapp_filter(nil, [:impressionable_type, :impressionable_id])
+      Impression.should have(@impression_count + 2).records
+    end
+
+    it "should recognize combined uniqueness" do
+      controller.stub!(:action_name).and_return("test_action")
+      controller.impressionist_subapp_filter(nil, [:ip_address, :request_hash, :action_name])
+      controller.impressionist_subapp_filter(nil, [:request_hash, :ip_address, :action_name])
+      controller.impressionist_subapp_filter(nil, [:request_hash, :action_name])
+      controller.impressionist_subapp_filter(nil, [:ip_address, :action_name])
+      controller.impressionist_subapp_filter(nil, [:ip_address, :request_hash])
+      controller.impressionist_subapp_filter(nil, [:action_name])
+      controller.impressionist_subapp_filter(nil, [:ip_address])
+      controller.impressionist_subapp_filter(nil, [:request_hash])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize combined non-uniqueness" do
+      controller.stub!(:action_name).and_return(nil)
+      controller.impressionist_subapp_filter(nil, [:ip_address, :action_name])
+      controller.stub!(:action_name).and_return("test_action")
+      controller.impressionist_subapp_filter(nil, [:ip_address, :action_name])
+      controller.stub!(:action_name).and_return("another_action")
+      controller.impressionist_subapp_filter(nil, [:ip_address, :action_name])
+      Impression.should have(@impression_count + 3).records
+    end
+
+  end
+
+  describe "impressionist method uniqueness for impressionables" do
+
+    # in this test we reuse the post model. might break if model changes.
+
+    it "should ignore uniqueness if not requested" do
+      impressionable = Post.create
+      controller.impressionist impressionable
+      controller.impressionist impressionable
+      Impression.should have(@impression_count + 2).records
+    end
+
+    it "should recognize unique session" do
+      # the following line was necessary as session hash returned a binary string (ASCII-8BIT encoded)
+      controller.stub!(:session_hash).and_return(request.session_options[:id].encode("ISO-8859-1"))
+      impressionable = Post.create
+      controller.impressionist(impressionable, nil, :unique => [:session_hash])
+      controller.impressionist(impressionable, nil, :unique => [:session_hash])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize unique ip" do
+      controller.request.stub!(:remote_ip).and_return("1.2.3.4")
+      impressionable = Post.create
+      controller.impressionist(impressionable, nil, :unique => [:ip_address])
+      controller.impressionist(impressionable, nil, :unique => [:ip_address])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize unique request" do
+      impressionable = Post.create
+      controller.impressionist(impressionable, nil, :unique => [:request_hash])
+      controller.impressionist(impressionable, nil, :unique => [:request_hash])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize unique user" do
+      controller.stub!(:user_id).and_return(666)
+      impressionable = Post.create
+      controller.impressionist(impressionable, nil, :unique => [:user_id])
+      controller.impressionist(impressionable, nil, :unique => [:user_id])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize unique referer" do
+      controller.request.stub!(:referer).and_return("http://foo/bar")
+      impressionable = Post.create
+      controller.impressionist(impressionable, nil, :unique => [:referrer])
+      controller.impressionist(impressionable, nil, :unique => [:referrer])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize different session" do
+      impressionable = Post.create
+      controller.stub!(:session_hash).and_return("foo")
+      controller.impressionist(impressionable, nil, :unique => [:session_hash])
+      controller.impressionist(impressionable, nil, :unique => [:session_hash])
+      Impression.should have(@impression_count + 1).records
+      controller.stub!(:session_hash).and_return("bar")
+      controller.impressionist(impressionable, nil, :unique => [:session_hash])
+      controller.impressionist(impressionable, nil, :unique => [:session_hash])
+      Impression.should have(@impression_count + 2).records
+    end
+
+    it "should recognize different ip" do
+      controller.request.stub!(:remote_ip).and_return("1.2.3.4")
+      impressionable = Post.create
+      controller.impressionist(impressionable, nil, :unique => [:ip_address])
+      controller.impressionist(impressionable, nil, :unique => [:ip_address])
+      Impression.should have(@impression_count + 1).records
+      controller.request.stub!(:remote_ip).and_return("5.6.7.8")
+      controller.impressionist(impressionable, nil, :unique => [:ip_address])
+      controller.impressionist(impressionable, nil, :unique => [:ip_address])
+      Impression.should have(@impression_count + 2).records
+    end
+
+    it "should recognize different user" do
+      impressionable = Post.create
+      controller.stub!(:user_id).and_return(666)
+      controller.impressionist(impressionable, nil, :unique => [:user_id])
+      controller.impressionist(impressionable, nil, :unique => [:user_id])
+      Impression.should have(@impression_count + 1).records
+      controller.stub!(:user_id).and_return(42)
+      controller.impressionist(impressionable, nil, :unique => [:user_id])
+      controller.impressionist(impressionable, nil, :unique => [:user_id])
+      Impression.should have(@impression_count + 2).records
+    end
+
+    it "should recognize combined uniqueness" do
+      impressionable = Post.create
+      controller.stub!(:session_hash).and_return("foo")
+      controller.impressionist(impressionable, nil, :unique => [:ip_address, :request_hash, :session_hash])
+      controller.impressionist(impressionable, nil, :unique => [:request_hash, :ip_address, :session_hash])
+      controller.impressionist(impressionable, nil, :unique => [:request_hash, :session_hash])
+      controller.impressionist(impressionable, nil, :unique => [:ip_address, :session_hash])
+      controller.impressionist(impressionable, nil, :unique => [:ip_address, :request_hash])
+      controller.impressionist(impressionable, nil, :unique => [:session_hash])
+      controller.impressionist(impressionable, nil, :unique => [:ip_address])
+      controller.impressionist(impressionable, nil, :unique => [:request_hash])
+      Impression.should have(@impression_count + 1).records
+    end
+
+    it "should recognize combined non-uniqueness" do
+      impressionable = Post.create
+      controller.stub!(:session_hash).and_return(nil)
+      controller.impressionist(impressionable, nil, :unique => [:ip_address, :session_hash])
+      controller.stub!(:session_hash).and_return("foo")
+      controller.impressionist(impressionable, nil, :unique => [:ip_address, :session_hash])
+      controller.stub!(:session_hash).and_return("bar")
+      controller.impressionist(impressionable, nil, :unique => [:ip_address, :session_hash])
+      Impression.should have(@impression_count + 3).records
+    end
+
+  end
+
+  describe "impressionist filter and method uniqueness" do
+
+    it "should recognize uniqueness" do
+      impressionable = Post.create
+      controller.stub!(:controller_name).and_return("posts") # for correct impressionable type in filter
+      controller.stub!(:params).and_return({:id => impressionable.id.to_s}) # for correct impressionable id in filter
+      controller.stub!(:session_hash).and_return("foo")
+      controller.request.stub!(:remote_ip).and_return("1.2.3.4")
+      # order of the following methods is important for the test!
+      controller.impressionist_subapp_filter(nil, [:ip_address, :request_hash, :session_hash])
+      controller.impressionist(impressionable, nil, :unique => [:ip_address, :request_hash, :session_hash])
+      Impression.should have(@impression_count + 1).records
+    end
+
+  end
+
+end
+
diff --git a/test_app/spec/rails_generators/rails_generators_spec.rb b/test_app/spec/rails_generators/rails_generators_spec.rb
index 7059b22..38ffbff 100644
--- a/test_app/spec/rails_generators/rails_generators_spec.rb
+++ b/test_app/spec/rails_generators/rails_generators_spec.rb
@@ -1,6 +1,8 @@
 require 'spec_helper'
 require 'systemu'
 
+# FIXME this test might break the others if run before them
+#
 describe Impressionist do
   fixtures :articles,:impressions,:posts
   it "should delete existing migration and generate the migration file" do
diff --git a/test_app/spec/spec_helper.rb b/test_app/spec/spec_helper.rb
index 9b8b02c..f24601c 100644
--- a/test_app/spec/spec_helper.rb
+++ b/test_app/spec/spec_helper.rb
@@ -24,4 +24,10 @@ RSpec.configure do |config|
   # examples within a transaction, remove the following line or assign false
   # instead of true.
   config.use_transactional_fixtures = true
+  
+  # make the rails logger usable in the tests as logger.xxx "..."
+  def logger
+    Rails.logger
+  end
+  
 end