create an option to disable split testing

.gitignore

@@ -2,4 +2,5 @@
 .bundle
 Gemfile.lock
 pkg/*
-*.rbc
+*.rbc
+.idea

lib/split/configuration.rb

@@ -5,13 +5,15 @@ class Configuration
     attr_accessor :db_failover
     attr_accessor :db_failover_on_db_error
     attr_accessor :allow_multiple_experiments
+    attr_accessor :disable_split
 
     def initialize
       @robot_regex = /\b(Baidu|Gigabot|Googlebot|libwww-perl|lwp-trivial|msnbot|SiteUptime|Slurp|WordPress|ZIBB|ZyBorg)\b/i
       @ignore_ip_addresses = []
       @db_failover = false
       @db_failover_on_db_error = proc{|error|} # e.g. use Rails logger here
       @allow_multiple_experiments = false
+      @disable_split = false
     end
   end
-end
+end

lib/split/helper.rb

@@ -1,33 +1,14 @@
 module Split
   module Helper
     def ab_test(experiment_name, control, *alternatives)
-      puts 'WARNING: You should always pass the control alternative through as the second argument with any other alternatives as the third because the order of the hash is not preserved in ruby 1.8' if RUBY_VERSION.match(/1\.8/) && alternatives.length.zero?
-      begin
-        experiment = Split::Experiment.find_or_create(experiment_name, *([control] + alternatives))
-        if experiment.winner
-          ret = experiment.winner.name
-        else
-          if forced_alternative = override(experiment.name, experiment.alternative_names)
-            ret = forced_alternative
-          else
-            clean_old_versions(experiment)
-            begin_experiment(experiment) if exclude_visitor? or not_allowed_to_test?(experiment.key)
 
-            if ab_user[experiment.key] 
-              ret = ab_user[experiment.key]
+      puts 'WARNING: You should always pass the control alternative through as the second argument with any other alternatives as the third because the order of the hash is not preserved in ruby 1.8' if RUBY_VERSION.match(/1\.8/) && alternatives.length.zero?
+      ret = if Split.configuration.disable_split
+              control_variable(control)
             else
-              alternative = experiment.next_alternative
-              alternative.increment_participation
-              begin_experiment(experiment, alternative.name)
-              ret = alternative.name
+              experiment_variable(alternatives, control, experiment_name)
             end
-          end
-        end
-      rescue Errno::ECONNREFUSED => e
-        raise unless Split.configuration.db_failover
-        Split.configuration.db_failover_on_db_error.call(e)
-        ret = Hash === control ? control.keys.first : control
-      end
+
       if block_given?
         if defined?(capture) # a block in a rails view
           block = Proc.new { yield(ret) }
@@ -42,7 +23,7 @@ def ab_test(experiment_name, control, *alternatives)
     end
 
     def finished(experiment_name, options = {:reset => true})
-      return if exclude_visitor?
+      return if exclude_visitor? or Split.configuration.disable_split
       return unless (experiment = Split::Experiment.find(experiment_name))
       if alternative_name = ab_user[experiment.key]
         alternative = Split::Alternative.new(alternative_name, experiment_name)
@@ -76,7 +57,7 @@ def not_allowed_to_test?(experiment_key)
     end
 
     def doing_other_tests?(experiment_key)
-      ab_user.keys.reject{|k| k == experiment_key}.length > 0
+      ab_user.keys.reject { |k| k == experiment_key }.length > 0
     end
 
     def clean_old_versions(experiment)
@@ -87,7 +68,7 @@ def clean_old_versions(experiment)
 
     def old_versions(experiment)
       if experiment.version > 0
-        ab_user.keys.select{|k| k.match(Regexp.new(experiment.name))}.reject{|k| k == experiment.key}
+        ab_user.keys.select { |k| k.match(Regexp.new(experiment.name)) }.reject { |k| k == experiment.key }
       else
         []
       end
@@ -104,5 +85,44 @@ def is_ignored_ip_address?
         false
       end
     end
+
+
+    protected
+
+    def control_variable(control)
+      Hash === control ? control.keys.first : control
+    end
+
+    def experiment_variable(alternatives, control, experiment_name)
+      begin
+        experiment = Split::Experiment.find_or_create(experiment_name, *([control] + alternatives))
+        if experiment.winner
+          ret = experiment.winner.name
+        else
+          if forced_alternative = override(experiment.name, experiment.alternative_names)
+            ret = forced_alternative
+          else
+            clean_old_versions(experiment)
+            begin_experiment(experiment) if exclude_visitor? or not_allowed_to_test?(experiment.key)
+
+            if ab_user[experiment.key]
+              ret = ab_user[experiment.key]
+            else
+              alternative = experiment.next_alternative
+              alternative.increment_participation
+              begin_experiment(experiment, alternative.name)
+              ret = alternative.name
+            end
+          end
+        end
+      rescue Errno::ECONNREFUSED => e
+        raise unless Split.configuration.db_failover
+        Split.configuration.db_failover_on_db_error.call(e)
+        ret = control_variable(control)
+      end
+      ret
+    end
+
   end
+
 end

spec/configuration_spec.rb

@@ -9,5 +9,6 @@
     config.db_failover.should be_false
     config.db_failover_on_db_error.should be_a Proc
     config.allow_multiple_experiments.should be_false
+    config.disable_split.should be_false
   end
 end

spec/experiment_spec.rb

@@ -28,7 +28,7 @@
 
     Split::Experiment.find('basket_text').start_time.should == experiment_start_time
   end
-  
+
   it "should handle not having a start time" do
     experiment_start_time = Time.parse("Sat Mar 03 14:01:03")
     Time.stub(:now => experiment_start_time)
@@ -200,4 +200,7 @@
       same_experiment.alternatives.map(&:weight).should == [1, 2]
     end
   end
+
+
+
 end

spec/helper_spec.rb

@@ -85,7 +85,7 @@
       small = Split::Alternative.new('small', 'button_size')
       small.participant_count.should eql(0)
     end
-    
+
     it "should let a user participate in many experiment with allow_multiple_experiments option" do
       Split.configure do |config|
         config.allow_multiple_experiments = true
@@ -346,6 +346,37 @@
         end
       end
 
+      describe "disable split testing" do
+
+        before(:each) do
+          Split.configure do |config|
+            config.disable_split = true
+          end
+        end
+
+        after(:each) do
+          Split.configure do |config|
+            config.disable_split = false
+          end
+        end
+
+        it "should not attempt to connect to redis" do
+
+          lambda {
+            ab_test('link_color', 'blue', 'red')
+          }.should_not raise_error(Errno::ECONNREFUSED)
+        end
+
+        it "should return control variable" do
+          ab_test('link_color', 'blue', 'red').should eq('blue')
+          lambda {
+            finished('link_color')
+          }.should_not raise_error(Errno::ECONNREFUSED)
+        end
+
+      end
+
+
     end
 
     context 'and db_failover config option is turned on' do
@@ -398,6 +429,7 @@
         end
       end
 
+
     end
 
   end