Avoid hitting all active experiments when calling ab_finished

lib/split/helper.rb

@@ -45,7 +45,7 @@ def reset!(experiment)
     end
 
     def finish_experiment(experiment, options = { reset: true })
-      return false if active_experiments[experiment.name].nil?
+      return false if ab_user[experiment.key].nil?
       return true if experiment.has_winner?
       should_reset = experiment.resettable? && options[:reset]
       if ab_user[experiment.finished_key] && !should_reset

spec/helper_spec.rb

@@ -402,6 +402,25 @@
         expect(ab_user.keys).to be_empty
       end
 
+      context "when an override is present for the experiment" do
+        it "should not increment the completed counter" do
+          @params = { "ab_test" => { @experiment_name => @alternative_name } }
+
+          expect {
+            ab_finished(@experiment_name)
+          }.not_to change { Split::Alternative.new(@alternative_name, @experiment_name).completed_count }
+        end
+
+        it "should not touch the user's participation" do
+          @params = { "ab_test" => { @experiment_name => @alternative_name } }
+
+          ab_finished(@experiment_name)
+
+          expect(ab_user[@experiment.key]).to eq(@alternative_name)
+          expect(ab_user[@experiment.finished_key]).to be_nil
+        end
+      end
+
       context "when on_trial_complete is set" do
         before { Split.configuration.on_trial_complete = :some_method }
         it "should call the method" do