added functionality to filter by message

app/models/impressionist/impressionable.rb

@@ -31,6 +31,10 @@ module Impressionist
       # If a start_date is provided, finds impressions between then and the end_date. Otherwise returns all impressions
       imps = options[:start_date].blank? ? impressions : impressions.where("created_at >= ? and created_at <= ?", options[:start_date], options[:end_date])
 
+      if options[:message]
+        imps = imps.where("impressions.message = ?", options[:message])
+      end
+
       # Count all distinct impressions unless the :all filter is provided.
       distinct = options[:filter] != :all
       if Rails::VERSION::MAJOR == 4

tests/test_app/spec/models/model_spec.rb

@@ -17,6 +17,14 @@ describe Impression do
     @article.impressions.last.message.should eq "test message"
   end
 
+  it "should return the impression count for the message specified" do
+    @article.impressions.create(:message => "pageview")
+    @article.impressions.create(:message => "pageview")
+    @article.impressions.create(:message => "visit")
+
+    @article.impressionist_count(:message => "pageview", :filter => :all).should eq 2
+  end
+
   it "should return the impression count for all with no date range specified" do
     @article.impressionist_count(:filter=>:all).should eq 11
   end