helper_spec.rb

# frozen_string_literal: true

require "spec_helper"

# TODO change some of these tests to use Rack::Test

describe Split::Helper do
  include Split::Helper

  let(:experiment) {
    Split::ExperimentCatalog.find_or_create("link_color", "blue", "red")
  }

  describe "ab_test" do
    it "should not raise an error when passed strings for alternatives" do
      expect { ab_test("xyz", "1", "2", "3") }.not_to raise_error
    end

    it "should not raise an error when passed an array for alternatives" do
      expect { ab_test("xyz", ["1", "2", "3"]) }.not_to raise_error
    end

    it "should raise the appropriate error when passed integers for alternatives" do
      expect { ab_test("xyz", 1, 2, 3) }.to raise_error(ArgumentError)
    end

    it "should raise the appropriate error when passed symbols for alternatives" do
      expect { ab_test("xyz", :a, :b, :c) }.to raise_error(ArgumentError)
    end

    it "should not raise error when passed an array for goals" do
      expect { ab_test({ "link_color" => ["purchase", "refund"] }, "blue", "red") }.not_to raise_error
    end

    it "should not raise error when passed just one goal" do
      expect { ab_test({ "link_color" => "purchase" }, "blue", "red") }.not_to raise_error
    end

    it "raises an appropriate error when processing combined expirements" do
      Split.configuration.experiments = {
        combined_exp_1: {
          alternatives: [  { name: "control", percent: 50 },  { name: "test-alt", percent: 50 } ],
          metric: :my_metric,
          combined_experiments: [:combined_exp_1_sub_1]
        }
      }
      Split::ExperimentCatalog.find_or_create("combined_exp_1")
      expect { ab_test("combined_exp_1") }.to raise_error(Split::InvalidExperimentsFormatError)
    end

    it "should assign a random alternative to a new user when there are an equal number of alternatives assigned" do
      ab_test("link_color", "blue", "red")
      expect(["red", "blue"]).to include(ab_user["link_color"])
    end

    it "should increment the participation counter after assignment to a new user" do
      previous_red_count = Split::Alternative.new("red", "link_color").participant_count
      previous_blue_count = Split::Alternative.new("blue", "link_color").participant_count

      ab_test("link_color", "blue", "red")

      new_red_count = Split::Alternative.new("red", "link_color").participant_count
      new_blue_count = Split::Alternative.new("blue", "link_color").participant_count

      expect((new_red_count + new_blue_count)).to eq(previous_red_count + previous_blue_count + 1)
    end

    it "should not increment the counter for an experiment that the user is not participating in" do
      ab_test("link_color", "blue", "red")
      e = Split::ExperimentCatalog.find_or_create("button_size", "small", "big")
      expect {
        # User shouldn't participate in this second experiment
        ab_test("button_size", "small", "big")
      }.not_to change { e.participant_count }
    end

    it "should not increment the counter for an ended experiment" do
      e = Split::ExperimentCatalog.find_or_create("button_size", "small", "big")
      e.winner = "small"
      expect {
        a = ab_test("button_size", "small", "big")
        expect(a).to eq("small")
      }.not_to change { e.participant_count }
    end

    it "should not increment the counter for an not started experiment" do
      expect(Split.configuration).to receive(:start_manually).and_return(true)
      e = Split::ExperimentCatalog.find_or_create("button_size", "small", "big")
      expect {
        a = ab_test("button_size", "small", "big")
        expect(a).to eq("small")
      }.not_to change { e.participant_count }
    end

    it "should return the given alternative for an existing user" do
      expect(ab_test("link_color", "blue", "red")).to eq ab_test("link_color", "blue", "red")
    end

    it "should always return the winner if one is present" do
      experiment.winner = "orange"

      expect(ab_test("link_color", "blue", "red")).to eq("orange")
    end

    it "should allow the alternative to be forced by passing it in the params" do
      # ?ab_test[link_color]=blue
      @params = { "ab_test" => { "link_color" => "blue" } }

      alternative = ab_test("link_color", "blue", "red")
      expect(alternative).to eq("blue")

      alternative = ab_test("link_color", { "blue" => 1 }, "red" => 5)
      expect(alternative).to eq("blue")

      @params = { "ab_test" => { "link_color" => "red" } }

      alternative = ab_test("link_color", "blue", "red")
      expect(alternative).to eq("red")

      alternative = ab_test("link_color", { "blue" => 5 }, "red" => 1)
      expect(alternative).to eq("red")
    end

    it "should not allow an arbitrary alternative" do
      @params = { "ab_test" => { "link_color" => "pink" } }
      alternative = ab_test("link_color", "blue")
      expect(alternative).to eq("blue")
    end

    it "should not store the split when a param forced alternative" do
      @params = { "ab_test" => { "link_color" => "blue" } }
      expect(ab_user).not_to receive(:[]=)
      ab_test("link_color", "blue", "red")
    end

    it "SPLIT_DISABLE query parameter should also force the alternative (uses control)" do
      @params = { "SPLIT_DISABLE" => "true" }
      alternative = ab_test("link_color", "blue", "red")
      expect(alternative).to eq("blue")
      alternative = ab_test("link_color", { "blue" => 1 }, "red" => 5)
      expect(alternative).to eq("blue")
      alternative = ab_test("link_color", "red", "blue")
      expect(alternative).to eq("red")
      alternative = ab_test("link_color", { "red" => 5 }, "blue" => 1)
      expect(alternative).to eq("red")
    end

    it "should not store the split when Split generically disabled" do
      @params = { "SPLIT_DISABLE" => "true" }
      expect(ab_user).not_to receive(:[]=)
      ab_test("link_color", "blue", "red")
    end

    context "when store_override is set" do
      before { Split.configuration.store_override = true }

      it "should store the forced alternative" do
        @params = { "ab_test" => { "link_color" => "blue" } }
        expect(ab_user).to receive(:[]=).with("link_color", "blue")
        ab_test("link_color", "blue", "red")
      end
    end

    context "when on_trial_choose is set" do
      before { Split.configuration.on_trial_choose = :some_method }
      it "should call the method" do
        expect(self).to receive(:some_method)
        ab_test("link_color", "blue", "red")
      end
    end

    it "should allow passing a block" do
      alt = ab_test("link_color", "blue", "red")
      ret = ab_test("link_color", "blue", "red") { |alternative| "shared/#{alternative}" }
      expect(ret).to eq("shared/#{alt}")
    end

    it "should allow the share of visitors see an alternative to be specified" do
      ab_test("link_color", { "blue" => 0.8 }, { "red" => 20 })
      expect(["red", "blue"]).to include(ab_user["link_color"])
    end

    it "should allow alternative weighting interface as a single hash" do
      ab_test("link_color", { "blue" => 0.01 }, "red" => 0.2)
      experiment = Split::ExperimentCatalog.find("link_color")
      expect(experiment.alternatives.map(&:name)).to eq(["blue", "red"])
      expect(experiment.alternatives.collect { |a| a.weight }).to match_array([0.01, 0.2])
    end

    it "should only let a user participate in one experiment at a time" do
      link_color = ab_test("link_color", "blue", "red")
      ab_test("button_size", "small", "big")
      expect(ab_user["link_color"]).to eq(link_color)
      big = Split::Alternative.new("big", "button_size")
      expect(big.participant_count).to eq(0)
      small = Split::Alternative.new("small", "button_size")
      expect(small.participant_count).to eq(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
      end
      link_color = ab_test("link_color", "blue", "red")
      button_size = ab_test("button_size", "small", "big")
      expect(ab_user["link_color"]).to eq(link_color)
      expect(ab_user["button_size"]).to eq(button_size)
      button_size_alt = Split::Alternative.new(button_size, "button_size")
      expect(button_size_alt.participant_count).to eq(1)
    end

    context "with allow_multiple_experiments = 'control'" do
      it "should let a user participate in many experiment with one non-'control' alternative" do
        Split.configure do |config|
          config.allow_multiple_experiments = "control"
        end
        groups = 100.times.map do |n|
          ab_test("test#{n}".to_sym, { "control" => (100 - n) }, { "test#{n}-alt" => n })
        end

        experiments = ab_user.active_experiments
        expect(experiments.size).to be > 1

        count_control = experiments.values.count { |g| g == "control" }
        expect(count_control).to eq(experiments.size - 1)

        count_alts = groups.count { |g| g != "control" }
        expect(count_alts).to eq(1)
      end

      context "when user already has experiment" do
        let(:mock_user) { Split::User.new(self, { "test_0" => "test-alt" }) }

        before do
          Split.configure do |config|
            config.allow_multiple_experiments = "control"
          end

          Split::ExperimentCatalog.find_or_initialize("test_0", "control", "test-alt").save
          Split::ExperimentCatalog.find_or_initialize("test_1", "control", "test-alt").save
        end

        it "should restore previously selected alternative" do
          expect(ab_user.active_experiments.size).to eq 1
          expect(ab_test(:test_0, { "control" => 100 }, { "test-alt" => 1 })).to eq "test-alt"
          expect(ab_test(:test_0, { "control" => 1 }, { "test-alt" => 100 })).to eq "test-alt"
        end

        it "should select the correct alternatives after experiment resets" do
          experiment = Split::ExperimentCatalog.find(:test_0)
          experiment.reset
          mock_user[experiment.key] = "test-alt"

          expect(ab_user.active_experiments.size).to eq 1
          expect(ab_test(:test_0, { "control" => 100 }, { "test-alt" => 1 })).to eq "test-alt"
          expect(ab_test(:test_0, { "control" => 0 }, { "test-alt" => 100 })).to eq "test-alt"
        end

        it "lets override existing choice" do
          pending "this requires user store reset on first call not depending on whelther it is current trial"
          @params = { "ab_test" => { "test_1" => "test-alt" } }

          expect(ab_test(:test_0, { "control" => 0 }, { "test-alt" => 100 })).to eq "control"
          expect(ab_test(:test_1, { "control" => 100 }, { "test-alt" => 1 })).to eq "test-alt"
        end
      end
    end

    it "should not over-write a finished key when an experiment is on a later version" do
      experiment.increment_version
      ab_user = { experiment.key => "blue", experiment.finished_key => true }
      finished_session = ab_user.dup
      ab_test("link_color", "blue", "red")
      expect(ab_user).to eq(finished_session)
    end
  end

  describe "metadata" do
    context "is defined" do
      before do
        Split.configuration.experiments = {
          my_experiment: {
            alternatives: ["one", "two"],
            resettable: false,
            metadata: { "one" => "Meta1", "two" => "Meta2" }
          }
        }
      end

      it "should be passed to helper block" do
        @params = { "ab_test" => { "my_experiment" => "two" } }
        expect(ab_test("my_experiment")).to eq "two"
        expect(ab_test("my_experiment") do |alternative, meta|
          meta
        end).to eq("Meta2")
      end

      it "should pass control metadata helper block if library disabled" do
        Split.configure do |config|
          config.enabled = false
        end

        expect(ab_test("my_experiment")).to eq "one"
        expect(ab_test("my_experiment") do |_, meta|
          meta
        end).to eq("Meta1")
      end
    end

    context "is not defined" do
      before do
        Split.configuration.experiments = {
          my_experiment: {
            alternatives: ["one", "two"],
            resettable: false,
            metadata: nil
          }
        }
      end

      it "should be passed to helper block" do
        expect(ab_test("my_experiment") do |alternative, meta|
          meta
        end).to eq({})
      end

      it "should pass control metadata helper block if library disabled" do
        Split.configure do |config|
          config.enabled = false
        end

        expect(ab_test("my_experiment") do |_, meta|
          meta
        end).to eq({})
      end
    end
  end

  describe "ab_finished" do
    context "for an experiment that the user participates in" do
      before(:each) do
        @experiment_name = "link_color"
        @alternatives = ["blue", "red"]
        @experiment = Split::ExperimentCatalog.find_or_create(@experiment_name, *@alternatives)
        @alternative_name = ab_test(@experiment_name, *@alternatives)
        @previous_completion_count = Split::Alternative.new(@alternative_name, @experiment_name).completed_count
      end

      it "should increment the counter for the completed alternative" do
        ab_finished(@experiment_name)
        new_completion_count = Split::Alternative.new(@alternative_name, @experiment_name).completed_count
        expect(new_completion_count).to eq(@previous_completion_count + 1)
      end

      it "should set experiment's finished key if reset is false" do
        ab_finished(@experiment_name, { reset: false })
        expect(ab_user[@experiment.key]).to eq(@alternative_name)
        expect(ab_user[@experiment.finished_key]).to eq(true)
      end

      it "should not increment the counter if reset is false and the experiment has been already finished" do
        2.times { ab_finished(@experiment_name, { reset: false }) }
        new_completion_count = Split::Alternative.new(@alternative_name, @experiment_name).completed_count
        expect(new_completion_count).to eq(@previous_completion_count + 1)
      end

      it "should not increment the counter for an ended experiment" do
        e = Split::ExperimentCatalog.find_or_create("button_size", "small", "big")
        e.winner = "small"
        a = ab_test("button_size", "small", "big")
        expect(a).to eq("small")
        expect {
          ab_finished("button_size")
        }.not_to change { Split::Alternative.new(a, "button_size").completed_count }
      end

      it "should clear out the user's participation from their session" do
        expect(ab_user[@experiment.key]).to eq(@alternative_name)
        ab_finished(@experiment_name)
        expect(ab_user.keys).to be_empty
      end

      it "should not clear out the users session if reset is false" do
        expect(ab_user[@experiment.key]).to eq(@alternative_name)
        ab_finished(@experiment_name, { reset: false })
        expect(ab_user[@experiment.key]).to eq(@alternative_name)
        expect(ab_user[@experiment.finished_key]).to eq(true)
      end

      it "should reset the users session when experiment is not versioned" do
        expect(ab_user[@experiment.key]).to eq(@alternative_name)
        ab_finished(@experiment_name)
        expect(ab_user.keys).to be_empty
      end

      it "should reset the users session when experiment is versioned" do
        @experiment.increment_version
        @alternative_name = ab_test(@experiment_name, *@alternatives)

        expect(ab_user[@experiment.key]).to eq(@alternative_name)
        ab_finished(@experiment_name)
        expect(ab_user.keys).to be_empty
      end

      context "when on_trial_complete is set" do
        before { Split.configuration.on_trial_complete = :some_method }
        it "should call the method" do
          expect(self).to receive(:some_method)
          ab_finished(@experiment_name)
        end

        it "should not call the method without alternative" do
          ab_user[@experiment.key] = nil
          expect(self).not_to receive(:some_method)
          ab_finished(@experiment_name)
        end
      end
    end

    context "for an experiment that the user is excluded from" do
      before do
        alternative = ab_test("link_color", "blue", "red")
        expect(Split::Alternative.new(alternative, "link_color").participant_count).to eq(1)
        alternative = ab_test("button_size", "small", "big")
        expect(Split::Alternative.new(alternative, "button_size").participant_count).to eq(0)
      end

      it "should not increment the completed counter" do
        # So, user should be participating in the link_color experiment and
        # receive the control for button_size. As the user is not participating in
        # the button size experiment, finishing it should not increase the
        # completion count for that alternative.
        expect {
          ab_finished("button_size")
        }.not_to change { Split::Alternative.new("small", "button_size").completed_count }
      end
    end

    context "for an experiment that the user does not participate in" do
      before do
        Split::ExperimentCatalog.find_or_create(:not_started_experiment, "control", "alt")
      end
      it "should not raise an exception" do
        expect { ab_finished(:not_started_experiment) }.not_to raise_exception
      end

      it "should not change the user state when reset is false" do
        expect { ab_finished(:not_started_experiment, reset: false) }.not_to change { ab_user.keys }.from([])
      end

      it "should not change the user state when reset is true" do
        expect(self).not_to receive(:reset!)
        ab_finished(:not_started_experiment)
      end

      it "should not increment the completed counter" do
        ab_finished(:not_started_experiment)
        expect(Split::Alternative.new("control", :not_started_experiment).completed_count).to eq(0)
        expect(Split::Alternative.new("alt", :not_started_experiment).completed_count).to eq(0)
      end
    end
  end

  context "finished with config" do
    it "passes reset option" do
      Split.configuration.experiments = {
        my_experiment: {
          alternatives: ["one", "two"],
          resettable: false,
        }
      }
      alternative = ab_test(:my_experiment)
      experiment = Split::ExperimentCatalog.find :my_experiment

      ab_finished :my_experiment
      expect(ab_user[experiment.key]).to eq(alternative)
      expect(ab_user[experiment.finished_key]).to eq(true)
    end
  end

  context "finished with metric name" do
    before { Split.configuration.experiments = {} }
    before { expect(Split::Alternative).to receive(:new).at_least(1).times.and_call_original }

    def should_finish_experiment(experiment_name, should_finish = true)
      alts = Split.configuration.experiments[experiment_name][:alternatives]
      experiment = Split::ExperimentCatalog.find_or_create(experiment_name, *alts)
      alt_name = ab_user[experiment.key] = alts.first
      alt = double("alternative")
      expect(alt).to receive(:name).at_most(1).times.and_return(alt_name)
      expect(Split::Alternative).to receive(:new).at_most(1).times.with(alt_name, experiment_name.to_s).and_return(alt)
      if should_finish
        expect(alt).to receive(:increment_completion).at_most(1).times
      else
        expect(alt).not_to receive(:increment_completion)
      end
    end

    it "completes the test" do
      Split.configuration.experiments[:my_experiment] = {
        alternatives: [ "control_opt", "other_opt" ],
        metric: :my_metric
      }
      should_finish_experiment :my_experiment
      ab_finished :my_metric
    end

    it "completes all relevant tests" do
      Split.configuration.experiments = {
        exp_1: {
          alternatives: [ "1-1", "1-2" ],
          metric: :my_metric
        },
        exp_2: {
          alternatives: [ "2-1", "2-2" ],
          metric: :another_metric
        },
        exp_3: {
          alternatives: [ "3-1", "3-2" ],
          metric: :my_metric
        },
      }
      should_finish_experiment :exp_1
      should_finish_experiment :exp_2, false
      should_finish_experiment :exp_3
      ab_finished :my_metric
    end

    it "passes reset option" do
      Split.configuration.experiments = {
        my_exp: {
          alternatives: ["one", "two"],
          metric: :my_metric,
          resettable: false,
        }
      }
      alternative_name = ab_test(:my_exp)
      exp = Split::ExperimentCatalog.find :my_exp

      ab_finished :my_metric
      expect(ab_user[exp.key]).to eq(alternative_name)
      expect(ab_user[exp.finished_key]).to be_truthy
    end

    it "passes through options" do
      Split.configuration.experiments = {
        my_exp: {
          alternatives: ["one", "two"],
          metric: :my_metric,
        }
      }
      alternative_name = ab_test(:my_exp)
      exp = Split::ExperimentCatalog.find :my_exp

      ab_finished :my_metric, reset: false
      expect(ab_user[exp.key]).to eq(alternative_name)
      expect(ab_user[exp.finished_key]).to be_truthy
    end
  end


  describe "ab_record_extra_info" do
    context "for an experiment that the user participates in" do
      before(:each) do
        @experiment_name = "link_color"
        @alternatives = ["blue", "red"]
        @experiment = Split::ExperimentCatalog.find_or_create(@experiment_name, *@alternatives)
        @alternative_name = ab_test(@experiment_name, *@alternatives)
      end

      it "records extra data for a given experiment" do
        alternative = Split::Alternative.new(@alternative_name, "link_color")

        ab_record_extra_info(@experiment_name, "some_data", 10)

        expect(alternative.extra_info).to eql({ "some_data" => 10 })
      end

      it "records extra data for a given experiment" do
        alternative = Split::Alternative.new(@alternative_name, "link_color")

        ab_record_extra_info(@experiment_name, "some_data")

        expect(alternative.extra_info).to eql({ "some_data" => 1 })
      end

      it "records extra data for a given experiment" do
        alternative = Split::Alternative.new(@alternative_name, "link_color")

        ab_record_extra_info(@experiment_name, "some_data", nil)

        expect(alternative.extra_info).to eql({})
      end
    end
  end

  describe "conversions" do
    it "should return a conversion rate for an alternative" do
      alternative_name = ab_test("link_color", "blue", "red")

      previous_convertion_rate = Split::Alternative.new(alternative_name, "link_color").conversion_rate
      expect(previous_convertion_rate).to eq(0.0)

      ab_finished("link_color")

      new_convertion_rate = Split::Alternative.new(alternative_name, "link_color").conversion_rate
      expect(new_convertion_rate).to eq(1.0)
    end
  end

  describe "active experiments" do
    it "should show an active test" do
      alternative = ab_test("def", "4", "5", "6")
      expect(active_experiments.count).to eq 1
      expect(active_experiments.first[0]).to eq "def"
      expect(active_experiments.first[1]).to eq alternative
    end

    it "should show a finished test" do
      alternative = ab_test("def", "4", "5", "6")
      ab_finished("def", { reset: false })
      expect(active_experiments.count).to eq 1
      expect(active_experiments.first[0]).to eq "def"
      expect(active_experiments.first[1]).to eq alternative
    end

    it "should show an active test when an experiment is on a later version" do
      experiment.reset
      expect(experiment.version).to eq(1)
      ab_test("link_color", "blue", "red")
      expect(active_experiments.count).to eq 1
      expect(active_experiments.first[0]).to eq "link_color"
    end

    it "should show versioned tests properly" do
      10.times { experiment.reset }

      alternative = ab_test(experiment.name, "blue", "red")
      ab_finished(experiment.name, reset: false)

      expect(experiment.version).to eq(10)
      expect(active_experiments.count).to eq 1
      expect(active_experiments).to eq({ "link_color" => alternative })
    end

    it "should show multiple tests" do
      Split.configure do |config|
        config.allow_multiple_experiments = true
      end
      alternative = ab_test("def", "4", "5", "6")
      another_alternative = ab_test("ghi", "7", "8", "9")
      expect(active_experiments.count).to eq 2
      expect(active_experiments["def"]).to eq alternative
      expect(active_experiments["ghi"]).to eq another_alternative
    end

    it "should not show tests with winners" do
      Split.configure do |config|
        config.allow_multiple_experiments = true
      end
      e = Split::ExperimentCatalog.find_or_create("def", "4", "5", "6")
      e.winner = "4"
      ab_test("def", "4", "5", "6")
      another_alternative = ab_test("ghi", "7", "8", "9")
      expect(active_experiments.count).to eq 1
      expect(active_experiments.first[0]).to eq "ghi"
      expect(active_experiments.first[1]).to eq another_alternative
    end
  end

  describe "when user is a robot" do
    before(:each) do
      @request = OpenStruct.new(user_agent: "Googlebot/2.1 (+http://www.google.com/bot.html)")
    end

    describe "ab_test" do
      it "should return the control" do
        alternative = ab_test("link_color", "blue", "red")
        expect(alternative).to eq experiment.control.name
      end

      it "should not create a experiment" do
        ab_test("link_color", "blue", "red")
        expect(Split::Experiment.new("link_color")).to be_a_new_record
      end

      it "should not increment the participation count" do
        previous_red_count = Split::Alternative.new("red", "link_color").participant_count
        previous_blue_count = Split::Alternative.new("blue", "link_color").participant_count

        ab_test("link_color", "blue", "red")

        new_red_count = Split::Alternative.new("red", "link_color").participant_count
        new_blue_count = Split::Alternative.new("blue", "link_color").participant_count

        expect((new_red_count + new_blue_count)).to eq(previous_red_count + previous_blue_count)
      end
    end

    describe "finished" do
      it "should not increment the completed count" do
        alternative_name = ab_test("link_color", "blue", "red")

        previous_completion_count = Split::Alternative.new(alternative_name, "link_color").completed_count

        ab_finished("link_color")

        new_completion_count = Split::Alternative.new(alternative_name, "link_color").completed_count

        expect(new_completion_count).to eq(previous_completion_count)
      end
    end
  end

  describe "when providing custom ignore logic" do
    context "using a proc to configure custom logic" do
      before(:each) do
        Split.configure do |c|
          c.ignore_filter = proc { |request| true } # ignore everything
        end
      end

      it "ignores the ab_test" do
        ab_test("link_color", "blue", "red")

        red_count = Split::Alternative.new("red", "link_color").participant_count
        blue_count = Split::Alternative.new("blue", "link_color").participant_count
        expect((red_count + blue_count)).to be(0)
      end
    end
  end

  shared_examples_for "a disabled test" do
    describe "ab_test" do
      it "should return the control" do
        alternative = ab_test("link_color", "blue", "red")
        expect(alternative).to eq experiment.control.name
      end

      it "should not increment the participation count" do
        previous_red_count = Split::Alternative.new("red", "link_color").participant_count
        previous_blue_count = Split::Alternative.new("blue", "link_color").participant_count

        ab_test("link_color", "blue", "red")

        new_red_count = Split::Alternative.new("red", "link_color").participant_count
        new_blue_count = Split::Alternative.new("blue", "link_color").participant_count

        expect((new_red_count + new_blue_count)).to eq(previous_red_count + previous_blue_count)
      end
    end

    describe "finished" do
      it "should not increment the completed count" do
        alternative_name = ab_test("link_color", "blue", "red")

        previous_completion_count = Split::Alternative.new(alternative_name, "link_color").completed_count

        ab_finished("link_color")

        new_completion_count = Split::Alternative.new(alternative_name, "link_color").completed_count

        expect(new_completion_count).to eq(previous_completion_count)
      end
    end
  end

  describe "when ip address is ignored" do
    context "individually" do
      before(:each) do
        @request = OpenStruct.new(ip: "81.19.48.130")
        Split.configure do |c|
          c.ignore_ip_addresses << "81.19.48.130"
        end
      end

      it_behaves_like "a disabled test"
    end

    context "for a range" do
      before(:each) do
        @request = OpenStruct.new(ip: "81.19.48.129")
        Split.configure do |c|
          c.ignore_ip_addresses << /81\.19\.48\.[0-9]+/
        end
      end

      it_behaves_like "a disabled test"
    end

    context "using both a range and a specific value" do
      before(:each) do
        @request = OpenStruct.new(ip: "81.19.48.128")
        Split.configure do |c|
          c.ignore_ip_addresses << "81.19.48.130"
          c.ignore_ip_addresses << /81\.19\.48\.[0-9]+/
        end
      end

      it_behaves_like "a disabled test"
    end

    context "when ignored other address" do
      before do
        @request = OpenStruct.new(ip: "1.1.1.1")
        Split.configure do |c|
          c.ignore_ip_addresses << "81.19.48.130"
        end
      end

      it "works as usual" do
        alternative_name = ab_test("link_color", "red", "blue")
        expect {
          ab_finished("link_color")
        }.to change(Split::Alternative.new(alternative_name, "link_color"), :completed_count).by(1)
      end
    end
  end

  describe "when user is previewing" do
    before(:each) do
      @request = OpenStruct.new(headers: { "x-purpose" => "preview" })
    end

    it_behaves_like "a disabled test"
  end

  describe "versioned experiments" do
    it "should use version zero if no version is present" do
      alternative_name = ab_test("link_color", "blue", "red")
      expect(experiment.version).to eq(0)
      expect(ab_user["link_color"]).to eq(alternative_name)
    end

    it "should save the version of the experiment to the session" do
      experiment.reset
      expect(experiment.version).to eq(1)
      alternative_name = ab_test("link_color", "blue", "red")
      expect(ab_user["link_color:1"]).to eq(alternative_name)
    end

    it "should load the experiment even if the version is not 0" do
      experiment.reset
      expect(experiment.version).to eq(1)
      alternative_name = ab_test("link_color", "blue", "red")
      expect(ab_user["link_color:1"]).to eq(alternative_name)
      return_alternative_name = ab_test("link_color", "blue", "red")
      expect(return_alternative_name).to eq(alternative_name)
    end

    it "should reset the session of a user on an older version of the experiment" do
      alternative_name = ab_test("link_color", "blue", "red")
      expect(ab_user["link_color"]).to eq(alternative_name)
      alternative = Split::Alternative.new(alternative_name, "link_color")
      expect(alternative.participant_count).to eq(1)

      experiment.reset
      expect(experiment.version).to eq(1)
      alternative = Split::Alternative.new(alternative_name, "link_color")
      expect(alternative.participant_count).to eq(0)

      new_alternative_name = ab_test("link_color", "blue", "red")
      expect(ab_user["link_color:1"]).to eq(new_alternative_name)
      new_alternative = Split::Alternative.new(new_alternative_name, "link_color")
      expect(new_alternative.participant_count).to eq(1)
    end

    it "should cleanup old versions of experiments from the session" do
      alternative_name = ab_test("link_color", "blue", "red")
      expect(ab_user["link_color"]).to eq(alternative_name)
      alternative = Split::Alternative.new(alternative_name, "link_color")
      expect(alternative.participant_count).to eq(1)

      experiment.reset
      expect(experiment.version).to eq(1)
      alternative = Split::Alternative.new(alternative_name, "link_color")
      expect(alternative.participant_count).to eq(0)

      new_alternative_name = ab_test("link_color", "blue", "red")
      expect(ab_user["link_color:1"]).to eq(new_alternative_name)
    end

    it "should only count completion of users on the current version" do
      alternative_name = ab_test("link_color", "blue", "red")
      expect(ab_user["link_color"]).to eq(alternative_name)
      Split::Alternative.new(alternative_name, "link_color")

      experiment.reset
      expect(experiment.version).to eq(1)

      ab_finished("link_color")
      alternative = Split::Alternative.new(alternative_name, "link_color")
      expect(alternative.completed_count).to eq(0)
    end
  end

  context "when redis is not available" do
    before(:each) do
      expect(Split).to receive(:redis).at_most(5).times.and_raise(Errno::ECONNREFUSED.new)
    end

    context "and db_failover config option is turned off" do
      before(:each) do
        Split.configure do |config|
          config.db_failover = false
        end
      end

      describe "ab_test" do
        it "should raise an exception" do
          expect { ab_test("link_color", "blue", "red") }.to raise_error(Errno::ECONNREFUSED)
        end
      end

      describe "finished" do
        it "should raise an exception" do
          expect { ab_finished("link_color") }.to raise_error(Errno::ECONNREFUSED)
        end
      end

      describe "disable split testing" do
        before(:each) do
          Split.configure do |config|
            config.enabled = false
          end
        end

        it "should not attempt to connect to redis" do
          expect { ab_test("link_color", "blue", "red") }.not_to raise_error
        end

        it "should return control variable" do
          expect(ab_test("link_color", "blue", "red")).to eq("blue")
          expect { ab_finished("link_color") }.not_to raise_error
        end
      end
    end

    context "and db_failover config option is turned on" do
      before(:each) do
        Split.configure do |config|
          config.db_failover = true
        end
      end

      describe "ab_test" do
        it "should not raise an exception" do
          expect { ab_test("link_color", "blue", "red") }.not_to raise_error
        end

        it "should call db_failover_on_db_error proc with error as parameter" do
          Split.configure do |config|
            config.db_failover_on_db_error = proc do |error|
              expect(error).to be_a(Errno::ECONNREFUSED)
            end
          end

          expect(Split.configuration.db_failover_on_db_error).to receive(:call).and_call_original
          ab_test("link_color", "blue", "red")
        end

        it "should always use first alternative" do
          expect(ab_test("link_color", "blue", "red")).to eq("blue")
          expect(ab_test("link_color", { "blue" => 0.01 }, "red" => 0.2)).to eq("blue")
          expect(ab_test("link_color", { "blue" => 0.8 }, { "red" => 20 })).to eq("blue")
          expect(ab_test("link_color", "blue", "red") do |alternative|
            "shared/#{alternative}"
          end).to eq("shared/blue")
        end

        context "and db_failover_allow_parameter_override config option is turned on" do
          before(:each) do
            Split.configure do |config|
              config.db_failover_allow_parameter_override = true
            end
          end

          context "and given an override parameter" do
            it "should use given override instead of the first alternative" do
              @params = { "ab_test" => { "link_color" => "red" } }
              expect(ab_test("link_color", "blue", "red")).to eq("red")
              expect(ab_test("link_color", "blue", "red", "green")).to eq("red")
              expect(ab_test("link_color", { "blue" => 0.01 }, "red" => 0.2)).to eq("red")
              expect(ab_test("link_color", { "blue" => 0.8 }, { "red" => 20 })).to eq("red")
              expect(ab_test("link_color", "blue", "red") do |alternative|
                "shared/#{alternative}"
              end).to eq("shared/red")
            end
          end
        end

        context "and preloaded config given" do
          before do
            Split.configuration.experiments[:link_color] = {
              alternatives: [ "blue", "red" ],
            }
          end

          it "uses first alternative" do
            expect(ab_test(:link_color)).to eq("blue")
          end
        end
      end

      describe "finished" do
        it "should not raise an exception" do
          expect { ab_finished("link_color") }.not_to raise_error
        end

        it "should call db_failover_on_db_error proc with error as parameter" do
          Split.configure do |config|
            config.db_failover_on_db_error = proc do |error|
              expect(error).to be_a(Errno::ECONNREFUSED)
            end
          end

          expect(Split.configuration.db_failover_on_db_error).to receive(:call).and_call_original
          ab_finished("link_color")
        end
      end
    end
  end

  context "with preloaded config" do
    before { Split.configuration.experiments = {} }

    it "pulls options from config file" do
      Split.configuration.experiments[:my_experiment] = {
        alternatives: [ "control_opt", "other_opt" ],
        goals: ["goal1", "goal2"]
      }
      ab_test :my_experiment
      expect(Split::Experiment.new(:my_experiment).alternatives.map(&:name)).to eq([ "control_opt", "other_opt" ])
      expect(Split::Experiment.new(:my_experiment).goals).to eq([ "goal1", "goal2" ])
    end

    it "can be called multiple times" do
      Split.configuration.experiments[:my_experiment] = {
        alternatives: [ "control_opt", "other_opt" ],
        goals: ["goal1", "goal2"]
      }
      5.times { ab_test :my_experiment }
      experiment = Split::Experiment.new(:my_experiment)
      expect(experiment.alternatives.map(&:name)).to eq([ "control_opt", "other_opt" ])
      expect(experiment.goals).to eq([ "goal1", "goal2" ])
      expect(experiment.participant_count).to eq(1)
    end

    it "accepts multiple goals" do
      Split.configuration.experiments[:my_experiment] = {
        alternatives: [ "control_opt", "other_opt" ],
        goals: [ "goal1", "goal2", "goal3" ]
      }
      ab_test :my_experiment
      experiment = Split::Experiment.new(:my_experiment)
      expect(experiment.goals).to eq([ "goal1", "goal2", "goal3" ])
    end

    it "allow specifying goals to be optional" do
      Split.configuration.experiments[:my_experiment] = {
        alternatives: [ "control_opt", "other_opt" ]
      }
      experiment = Split::Experiment.new(:my_experiment)
      expect(experiment.goals).to eq([])
    end

    it "accepts multiple alternatives" do
      Split.configuration.experiments[:my_experiment] = {
        alternatives: [ "control_opt", "second_opt", "third_opt" ],
      }
      ab_test :my_experiment
      experiment = Split::Experiment.new(:my_experiment)
      expect(experiment.alternatives.map(&:name)).to eq([ "control_opt", "second_opt", "third_opt" ])
    end

    it "accepts probability on alternatives" do
      Split.configuration.experiments[:my_experiment] = {
        alternatives: [
          { name: "control_opt", percent: 67 },
          { name: "second_opt", percent: 10 },
          { name: "third_opt", percent: 23 },
        ],
      }
      ab_test :my_experiment
      experiment = Split::Experiment.new(:my_experiment)
      expect(experiment.alternatives.collect { |a| [a.name, a.weight] }).to eq([["control_opt", 0.67], ["second_opt", 0.1], ["third_opt", 0.23]])
    end

    it "accepts probability on some alternatives" do
      Split.configuration.experiments[:my_experiment] = {
        alternatives: [
          { name: "control_opt", percent: 34 },
          "second_opt",
          { name: "third_opt", percent: 23 },
          "fourth_opt",
        ],
      }
      ab_test :my_experiment
      experiment = Split::Experiment.new(:my_experiment)
      names_and_weights = experiment.alternatives.collect { |a| [a.name, a.weight] }
      expect(names_and_weights).to eq([["control_opt", 0.34], ["second_opt", 0.215], ["third_opt", 0.23], ["fourth_opt", 0.215]])
      expect(names_and_weights.inject(0) { |sum, nw| sum + nw[1] }).to eq(1.0)
    end

    it "allows name param without probability" do
      Split.configuration.experiments[:my_experiment] = {
        alternatives: [
          { name: "control_opt" },
          "second_opt",
          { name: "third_opt", percent: 64 },
        ],
      }
      ab_test :my_experiment
      experiment = Split::Experiment.new(:my_experiment)
      names_and_weights = experiment.alternatives.collect { |a| [a.name, a.weight] }
      expect(names_and_weights).to eq([["control_opt", 0.18], ["second_opt", 0.18], ["third_opt", 0.64]])
      expect(names_and_weights.inject(0) { |sum, nw| sum + nw[1] }).to eq(1.0)
    end

    it "fails gracefully if config is missing experiment" do
      Split.configuration.experiments = { other_experiment: { foo: "Bar" } }
      expect { ab_test :my_experiment }.to raise_error(Split::ExperimentNotFound)
    end

    it "fails gracefully if config is missing" do
      expect { Split.configuration.experiments = nil }.to raise_error(Split::InvalidExperimentsFormatError)
    end

    it "fails gracefully if config is missing alternatives" do
      Split.configuration.experiments[:my_experiment] = { foo: "Bar" }
      expect { ab_test :my_experiment }.to raise_error(NoMethodError)
    end
  end

  it "should handle multiple experiments correctly" do
    experiment2 = Split::ExperimentCatalog.find_or_create("link_color2", "blue", "red")
    ab_test("link_color", "blue", "red")
    ab_test("link_color2", "blue", "red")
    ab_finished("link_color2")

    experiment2.alternatives.each do |alt|
      expect(alt.unfinished_count).to eq(0)
    end
  end

  context "with goals" do
    before do
      @experiment = { "link_color" => ["purchase", "refund"] }
      @alternatives = ["blue", "red"]
      @experiment_name, @goals = normalize_metric(@experiment)
      @goal1 = @goals[0]
      @goal2 = @goals[1]
    end

    it "should normalize experiment" do
      expect(@experiment_name).to eq("link_color")
      expect(@goals).to eq(["purchase", "refund"])
    end

    describe "ab_test" do
      it "should allow experiment goals interface as a single hash" do
        ab_test(@experiment, *@alternatives)
        experiment = Split::ExperimentCatalog.find("link_color")
        expect(experiment.goals).to eq(["purchase", "refund"])
      end
    end

    describe "ab_finished" do
      before do
        @alternative_name = ab_test(@experiment, *@alternatives)
      end

      it "should increment the counter for the specified-goal completed alternative" do
        expect { ab_finished({ "link_color" => ["purchase"] }) }
          .to change { Split::Alternative.new(@alternative_name, @experiment_name).completed_count(@goal2) }.by(0)
          .and change { Split::Alternative.new(@alternative_name, @experiment_name).completed_count(@goal1) }.by(1)
      end
    end
  end
end