trial_spec.rb

require 'spec_helper'
require 'split/trial'

describe Split::Trial do
  let(:user) { Split::Persistence.adapter.new(double(session: {})) }
  let(:experiment) do
    Split::Experiment.new('basket_text', :alternatives => ['basket', 'cart']).save
  end

  it "should be initializeable" do
    experiment  = double('experiment')
    alternative = double('alternative', :kind_of? => Split::Alternative)
    trial = Split::Trial.new(:experiment => experiment, :alternative => alternative)
    expect(trial.experiment).to eq(experiment)
    expect(trial.alternative).to eq(alternative)
  end

  describe "alternative" do
    it "should use the alternative if specified" do
      alternative = double('alternative', :kind_of? => Split::Alternative)
      trial = Split::Trial.new(:experiment => experiment = double('experiment'),
          :alternative => alternative, :user => user)
      expect(trial).not_to receive(:choose)
      expect(trial.alternative).to eq(alternative)
    end

    it "should load the alternative when the alternative name is set" do
      experiment = Split::Experiment.new('basket_text', :alternatives => ['basket', 'cart'])
      experiment.save

      trial = Split::Trial.new(:experiment => experiment, :alternative => 'basket')
      expect(trial.alternative.name).to eq('basket')
    end
  end

  describe "metadata" do
    let(:alternatives) { ['basket', 'cart'] }
    let(:metadata) { Hash[alternatives.map { |k| [k, "Metadata for #{k}"] }] }
    let(:experiment) do
      Split::Experiment.new('basket_text', :alternatives => alternatives, :metadata => metadata).save
    end

    it 'has metadata on each trial' do
      trial = Split::Trial.new(:experiment => experiment, :user => user, :metadata => metadata['cart'],
                               :override => 'cart')
      expect(trial.metadata).to eq(metadata['cart'])
    end

    it 'has metadata on each trial from the experiment' do
      trial = Split::Trial.new(:experiment => experiment, :user => user)
      trial.choose!
      expect(trial.metadata).to eq(metadata[trial.alternative.name])
      expect(trial.metadata).to match /#{trial.alternative.name}/
    end
  end

  describe "#choose!" do
    def expect_alternative(trial, alternative_name)
      3.times do
        trial.choose!
        expect(trial.alternative.name).to eq(alternative_name)
      end
    end

    context "when override is present" do
      it "picks the override" do
        trial = Split::Trial.new(:user => user, :experiment => experiment, :override => 'cart')
        expect(experiment).to_not receive(:next_alternative)

        expect_alternative(trial, 'cart')
      end
    end

    context "when disabled option is true" do
      it "picks the control" do
        trial = Split::Trial.new(:user => user, :experiment => experiment, :disabled => true)
        expect(experiment).to_not receive(:next_alternative)

        expect_alternative(trial, 'basket')
      end
    end

    context "when Split is globally disabled" do
      it "picks the control" do
        Split.configuration.enabled = false
        trial = Split::Trial.new(:user => user, :experiment => experiment)
        expect(experiment).to_not receive(:next_alternative)

        expect_alternative(trial, 'basket')
        Split.configuration.enabled = true
      end
    end

    context "when experiment has winner" do
      it "picks the winner" do
        trial = Split::Trial.new(:user => user, :experiment => experiment)
        experiment.winner = 'cart'
        expect(experiment).to_not receive(:next_alternative)

        expect_alternative(trial, 'cart')
      end
    end

    context "when exclude is true" do
      it "picks the control" do
        trial = Split::Trial.new(:user => user, :experiment => experiment, :exclude => true)
        expect(experiment).to_not receive(:next_alternative)

        expect_alternative(trial, 'basket')
      end
    end

    context "when user is already participating" do
      it "picks the same alternative" do
        user[experiment.key] = 'basket'
        trial = Split::Trial.new(:user => user, :experiment => experiment)
        expect(experiment).to_not receive(:next_alternative)

        expect_alternative(trial, 'basket')
      end
    end

    context "when user is a new participant" do
      it "picks a new alternative" do
        trial = Split::Trial.new(:user => user, :experiment => experiment)
        expect(experiment).to receive(:next_alternative).and_call_original

        trial.choose!
        expect(trial.alternative.name).to_not be_empty
      end
    end

    describe "#complete!" do
      let(:trial) { Split::Trial.new(:user => user, :experiment => experiment) }
      context 'when there are no goals' do
        it 'should complete the trial' do
          trial.choose!
          old_completed_count = trial.alternative.completed_count
          trial.complete!
          expect(trial.alternative.completed_count).to be(old_completed_count+1)
        end
      end

      context 'when there are many goals' do
        let(:goals) { ['first', 'second'] }
        let(:trial) { Split::Trial.new(:user => user, :experiment => experiment, :goals => goals) }
        shared_examples_for "goal completion" do
          it 'should not complete the trial' do
            trial.choose!
            old_completed_count = trial.alternative.completed_count
            trial.complete!(goal)
            expect(trial.alternative.completed_count).to_not be(old_completed_count+1)
          end
        end

        describe 'Array of Goals' do
          let(:goal) { [goals.first] }
          it_behaves_like 'goal completion'
        end

        describe 'String of Goal' do
          let(:goal) { goals.first }
          it_behaves_like 'goal completion'
        end

      end
    end

    describe "alternative recording" do
      before(:each) { Split.configuration.store_override = false }

      context "when override is present" do
        it "stores when store_override is true" do
          trial = Split::Trial.new(:user => user, :experiment => experiment, :override => 'basket')

          Split.configuration.store_override = true
          expect(user).to receive("[]=")
          trial.choose!
        end

        it "does not store when store_override is false" do
          trial = Split::Trial.new(:user => user, :experiment => experiment, :override => 'basket')

          expect(user).to_not receive("[]=")
          trial.choose!
        end
      end

      context "when disabled is present" do
        it "stores when store_override is true" do
          trial = Split::Trial.new(:user => user, :experiment => experiment, :disabled => true)

          Split.configuration.store_override = true
          expect(user).to receive("[]=")
          trial.choose!
        end

        it "does not store when store_override is false" do
          trial = Split::Trial.new(:user => user, :experiment => experiment, :disabled => true)

          expect(user).to_not receive("[]=")
          trial.choose!
        end
      end

      context "when exclude is present" do
        it "does not store" do
          trial = Split::Trial.new(:user => user, :experiment => experiment, :exclude => true)

          expect(user).to_not receive("[]=")
          trial.choose!
        end
      end
    end
  end
end