Ensure variant when creating ExperimentSubjects

app/experiments/application_experiment.rb

@@ -32,8 +32,8 @@ class ApplicationExperiment < Gitlab::Experiment # rubocop:disable Gitlab/Namesp
     subject = value[:namespace] || value[:group] || value[:project] || value[:user] || value[:actor]
     return unless ExperimentSubject.valid_subject?(subject)
 
-    variant = :experimental if @variant_name != :control
-    Experiment.add_subject(name, variant: variant || :control, subject: subject)
+    variant_name = :experimental if variant&.name != 'control'
+    Experiment.add_subject(name, variant: variant_name || :control, subject: subject)
   end
 
   def record!

spec/experiments/application_experiment_spec.rb

@@ -3,7 +3,7 @@
 require 'spec_helper'
 
 RSpec.describe ApplicationExperiment, :experiment do
-  subject { described_class.new('namespaced/stub', **context) }
+  subject(:application_experiment) { described_class.new('namespaced/stub', **context) }
 
   let(:context) { {} }
   let(:feature_definition) { { name: 'namespaced_stub', type: 'experiment', default_enabled: false } }
@@ -15,7 +15,7 @@ RSpec.describe ApplicationExperiment, :experiment do
   end
 
   before do
-    allow(subject).to receive(:enabled?).and_return(true)
+    allow(application_experiment).to receive(:enabled?).and_return(true)
   end
 
   it "doesn't raise an exception without a defined control" do
@@ -26,7 +26,7 @@ RSpec.describe ApplicationExperiment, :experiment do
 
   describe "#enabled?" do
     before do
-      allow(subject).to receive(:enabled?).and_call_original
+      allow(application_experiment).to receive(:enabled?).and_call_original
 
       allow(Feature::Definition).to receive(:get).and_return('_instance_')
       allow(Gitlab).to receive(:dev_env_or_com?).and_return(true)
@@ -34,25 +34,25 @@ RSpec.describe ApplicationExperiment, :experiment do
     end
 
     it "is enabled when all criteria are met" do
-      expect(subject).to be_enabled
+      expect(application_experiment).to be_enabled
     end
 
     it "isn't enabled if the feature definition doesn't exist" do
       expect(Feature::Definition).to receive(:get).with('namespaced_stub').and_return(nil)
 
-      expect(subject).not_to be_enabled
+      expect(application_experiment).not_to be_enabled
     end
 
     it "isn't enabled if we're not in dev or dotcom environments" do
       expect(Gitlab).to receive(:dev_env_or_com?).and_return(false)
 
-      expect(subject).not_to be_enabled
+      expect(application_experiment).not_to be_enabled
     end
 
     it "isn't enabled if the feature flag state is :off" do
       expect(Feature).to receive(:get).with('namespaced_stub').and_return(double(state: :off))
 
-      expect(subject).not_to be_enabled
+      expect(application_experiment).not_to be_enabled
     end
   end
 
@@ -60,11 +60,11 @@ RSpec.describe ApplicationExperiment, :experiment do
     let(:should_track) { true }
 
     before do
-      allow(subject).to receive(:should_track?).and_return(should_track)
+      allow(application_experiment).to receive(:should_track?).and_return(should_track)
     end
 
     it "tracks the assignment", :snowplow do
-      subject.publish
+      application_experiment.publish
 
       expect_snowplow_event(
         category: 'namespaced/stub',
@@ -74,24 +74,24 @@ RSpec.describe ApplicationExperiment, :experiment do
     end
 
     it "publishes to the client" do
-      expect(subject).to receive(:publish_to_client)
+      expect(application_experiment).to receive(:publish_to_client)
 
-      subject.publish
+      application_experiment.publish
     end
 
     it "publishes to the database if we've opted for that" do
-      subject.record!
+      application_experiment.record!
 
-      expect(subject).to receive(:publish_to_database)
+      expect(application_experiment).to receive(:publish_to_database)
 
-      subject.publish
+      application_experiment.publish
     end
 
     context 'when we should not track' do
       let(:should_track) { false }
 
       it 'does not track an event to Snowplow', :snowplow do
-        subject.publish
+        application_experiment.publish
 
         expect_no_snowplow_event
       end
@@ -102,13 +102,13 @@ RSpec.describe ApplicationExperiment, :experiment do
         signature = { key: '86208ac54ca798e11f127e8b23ec396a', variant: 'control' }
         expect(Gon).to receive(:push).with({ experiment: { 'namespaced/stub' => hash_including(signature) } }, true)
 
-        subject.publish_to_client
+        application_experiment.publish_to_client
       end
 
       it "handles when Gon raises exceptions (like when it can't be pushed into)" do
         expect(Gon).to receive(:push).and_raise(NoMethodError)
 
-        expect { subject.publish_to_client }.not_to raise_error
+        expect { application_experiment.publish_to_client }.not_to raise_error
       end
 
       context 'when we should not track' do
@@ -117,7 +117,7 @@ RSpec.describe ApplicationExperiment, :experiment do
         it 'returns early' do
           expect(Gon).not_to receive(:push)
 
-          subject.publish_to_client
+          application_experiment.publish_to_client
         end
       end
     end
@@ -125,13 +125,15 @@ RSpec.describe ApplicationExperiment, :experiment do
     describe '#publish_to_database' do
       using RSpec::Parameterized::TableSyntax
 
+      let(:publish_to_database) { application_experiment.publish_to_database }
+
       shared_examples 'does not record to the database' do
         it 'does not create an experiment record' do
-          expect { subject.publish_to_database }.not_to change(Experiment, :count)
+          expect { publish_to_database }.not_to change(Experiment, :count)
         end
 
         it 'does not create an experiment subject record' do
-          expect { subject.publish_to_database }.not_to change(ExperimentSubject, :count)
+          expect { publish_to_database }.not_to change(ExperimentSubject, :count)
         end
       end
 
@@ -139,16 +141,16 @@ RSpec.describe ApplicationExperiment, :experiment do
         let(:context) { { context_key => context_value } }
 
         where(:context_key, :context_value, :object_type) do
-          :namespace | build(:namespace) | :namespace
-          :group     | build(:namespace) | :namespace
-          :project   | build(:project)   | :project
-          :user      | build(:user)      | :user
-          :actor     | build(:user)      | :user
+          :namespace | build(:namespace, id: non_existing_record_id) | :namespace
+          :group     | build(:namespace, id: non_existing_record_id) | :namespace
+          :project   | build(:project, id: non_existing_record_id)   | :project
+          :user      | build(:user, id: non_existing_record_id)      | :user
+          :actor     | build(:user, id: non_existing_record_id)      | :user
         end
 
         with_them do
           it 'creates an experiment and experiment subject record' do
-            expect { subject.publish_to_database }.to change(Experiment, :count).by(1)
+            expect { publish_to_database }.to change(Experiment, :count).by(1)
 
             expect(Experiment.last.name).to eq('namespaced/stub')
             expect(ExperimentSubject.last.send(object_type)).to eq(context[context_key])
@@ -156,6 +158,16 @@ RSpec.describe ApplicationExperiment, :experiment do
         end
       end
 
+      context "when experiment hasn't ran" do
+        let(:context) { { user: create(:user) } }
+
+        it 'sets a variant on the experiment subject' do
+          publish_to_database
+
+          expect(ExperimentSubject.last.variant).to eq('control')
+        end
+      end
+
       context 'when there is not a usable subject' do
         let(:context) { { context_key => context_value } }
 
@@ -183,15 +195,15 @@ RSpec.describe ApplicationExperiment, :experiment do
     end
 
     it "doesn't track if we shouldn't track" do
-      allow(subject).to receive(:should_track?).and_return(false)
+      allow(application_experiment).to receive(:should_track?).and_return(false)
 
-      subject.track(:action)
+      application_experiment.track(:action)
 
       expect_no_snowplow_event
     end
 
     it "tracks the event with the expected arguments and merged contexts" do
-      subject.track(:action, property: '_property_', context: [fake_context])
+      application_experiment.track(:action, property: '_property_', context: [fake_context])
 
       expect_snowplow_event(
         category: 'namespaced/stub',
@@ -233,7 +245,7 @@ RSpec.describe ApplicationExperiment, :experiment do
 
   describe "#key_for" do
     it "generates MD5 hashes" do
-      expect(subject.key_for(foo: :bar)).to eq('6f9ac12afdb9b58c2f19a136d09f9153')
+      expect(application_experiment.key_for(foo: :bar)).to eq('6f9ac12afdb9b58c2f19a136d09f9153')
     end
   end
 
@@ -256,26 +268,26 @@ RSpec.describe ApplicationExperiment, :experiment do
     with_them do
       it "returns the url or nil if invalid" do
         allow(Gitlab).to receive(:dev_env_or_com?).and_return(true)
-        expect(subject.process_redirect_url(url)).to eq(processed_url)
+        expect(application_experiment.process_redirect_url(url)).to eq(processed_url)
       end
 
       it "considers all urls invalid when not on dev or com" do
         allow(Gitlab).to receive(:dev_env_or_com?).and_return(false)
-        expect(subject.process_redirect_url(url)).to be_nil
+        expect(application_experiment.process_redirect_url(url)).to be_nil
       end
     end
 
     it "generates the correct urls based on where the engine was mounted" do
-      url = Rails.application.routes.url_helpers.experiment_redirect_url(subject, url: 'https://docs.gitlab.com')
-      expect(url).to include("/-/experiment/namespaced%2Fstub:#{subject.context.key}?https://docs.gitlab.com")
+      url = Rails.application.routes.url_helpers.experiment_redirect_url(application_experiment, url: 'https://docs.gitlab.com')
+      expect(url).to include("/-/experiment/namespaced%2Fstub:#{application_experiment.context.key}?https://docs.gitlab.com")
     end
   end
 
   context "when resolving variants" do
     it "uses the default value as specified in the yaml" do
-      expect(Feature).to receive(:enabled?).with('namespaced_stub', subject, type: :experiment, default_enabled: :yaml)
+      expect(Feature).to receive(:enabled?).with('namespaced_stub', application_experiment, type: :experiment, default_enabled: :yaml)
 
-      expect(subject.variant.name).to eq('control')
+      expect(application_experiment.variant.name).to eq('control')
     end
 
     context "when rolled out to 100%" do
@@ -284,10 +296,10 @@ RSpec.describe ApplicationExperiment, :experiment do
       end
 
       it "returns the first variant name" do
-        subject.try(:variant1) {}
-        subject.try(:variant2) {}
+        application_experiment.try(:variant1) {}
+        application_experiment.try(:variant2) {}
 
-        expect(subject.variant.name).to eq('variant1')
+        expect(application_experiment.variant.name).to eq('variant1')
       end
     end
   end
@@ -298,18 +310,18 @@ RSpec.describe ApplicationExperiment, :experiment do
     before do
       allow(Gitlab::Experiment::Configuration).to receive(:cache).and_call_original
 
-      cache.clear(key: subject.name)
+      cache.clear(key: application_experiment.name)
 
-      subject.use { } # setup the control
-      subject.try { } # setup the candidate
+      application_experiment.use { } # setup the control
+      application_experiment.try { } # setup the candidate
     end
 
     it "caches the variant determined by the variant resolver" do
-      expect(subject.variant.name).to eq('candidate') # we should be in the experiment
+      expect(application_experiment.variant.name).to eq('candidate') # we should be in the experiment
 
-      subject.run
+      application_experiment.run
 
-      expect(subject.cache.read).to eq('candidate')
+      expect(application_experiment.cache.read).to eq('candidate')
     end
 
     it "doesn't cache a variant if we don't explicitly provide one" do
@@ -320,11 +332,11 @@ RSpec.describe ApplicationExperiment, :experiment do
       # the control.
       stub_feature_flags(namespaced_stub: false) # simulate being not rolled out
 
-      expect(subject.variant.name).to eq('control') # if we ask, it should be control
+      expect(application_experiment.variant.name).to eq('control') # if we ask, it should be control
 
-      subject.run
+      application_experiment.run
 
-      expect(subject.cache.read).to be_nil
+      expect(application_experiment.cache.read).to be_nil
     end
 
     it "caches a control variant if we assign it specifically" do
@@ -332,27 +344,27 @@ RSpec.describe ApplicationExperiment, :experiment do
       # that this context will always get the control variant unless we delete
       # the field from the cache (or clear the entire experiment cache) -- or
       # write code that would specify a different variant.
-      subject.run(:control)
+      application_experiment.run(:control)
 
-      expect(subject.cache.read).to eq('control')
+      expect(application_experiment.cache.read).to eq('control')
     end
 
     context "arbitrary attributes" do
       before do
-        subject.cache.store.clear(key: subject.name + '_attrs')
+        application_experiment.cache.store.clear(key: application_experiment.name + '_attrs')
       end
 
       it "sets and gets attributes about an experiment" do
-        subject.cache.attr_set(:foo, :bar)
+        application_experiment.cache.attr_set(:foo, :bar)
 
-        expect(subject.cache.attr_get(:foo)).to eq('bar')
+        expect(application_experiment.cache.attr_get(:foo)).to eq('bar')
       end
 
       it "increments a value for an experiment" do
-        expect(subject.cache.attr_get(:foo)).to be_nil
+        expect(application_experiment.cache.attr_get(:foo)).to be_nil
 
-        expect(subject.cache.attr_inc(:foo)).to eq(1)
-        expect(subject.cache.attr_inc(:foo)).to eq(2)
+        expect(application_experiment.cache.attr_inc(:foo)).to eq(1)
+        expect(application_experiment.cache.attr_inc(:foo)).to eq(2)
       end
     end
   end