Implement reviewer feedback

app/experiments/application_experiment.rb

@@ -58,7 +58,7 @@ class ApplicationExperiment < Gitlab::Experiment # rubocop:disable Gitlab/Namesp
 
   def record_experiment
     subject = context.value[:namespace] || context.value[:group] || context.value[:project] || context.value[:user] || context.value[:actor]
-    return unless subject.is_a?(Namespace) || subject.is_a?(User) || subject.is_a?(Project)
+    return unless ExperimentSubject.valid_subject?(subject)
 
     variant = :experimental if @variant_name != :control
 

app/models/experiment.rb

@@ -42,9 +42,9 @@ class Experiment < ApplicationRecord
   end
 
   def record_subject_and_variant!(subject, variant)
-    raise 'Incompatible subject provided!' unless subject.is_a?(Namespace) || subject.is_a?(User) || subject.is_a?(Project)
+    raise 'Incompatible subject provided!' unless ExperimentSubject.valid_subject?(subject)
 
-    attr_name = subject.is_a?(Namespace) ? :namespace : subject.class.name.downcase.to_sym
+    attr_name = subject.class.table_name.singularize.to_sym
     experiment_subject = experiment_subjects.find_or_initialize_by(attr_name => subject)
     experiment_subject.assign_attributes(variant: variant)
     # We only call save when necessary because this causes the request to stick to the primary DB

app/models/experiment_subject.rb

@@ -14,6 +14,10 @@ class ExperimentSubject < ApplicationRecord
 
   enum variant: { GROUP_CONTROL => 0, GROUP_EXPERIMENTAL => 1 }
 
+  def self.valid_subject?(subject)
+    subject.is_a?(Namespace) || subject.is_a?(User) || subject.is_a?(Project)
+  end
+
   private
 
   def must_have_one_subject_present

spec/models/experiment_spec.rb

@@ -273,7 +273,7 @@ RSpec.describe Experiment do
 
     describe 'providing a subject to record' do
       context 'when given a group as subject' do
-        it 'saves the namespace owner as experiment_subject user' do
+        it 'saves the namespace as the experiment subject' do
           expect(record_subject_and_variant!.namespace).to eq(subject_to_record)
         end
       end
@@ -281,7 +281,7 @@ RSpec.describe Experiment do
       context 'when given a users namespace as subject' do
         let_it_be(:subject_to_record) { build(:namespace) }
 
-        it 'saves the namespace owner as experiment_subject user' do
+        it 'saves the namespace as the experiment_subject' do
           expect(record_subject_and_variant!.namespace).to eq(subject_to_record)
         end
       end

spec/models/experiment_subject_spec.rb

@@ -51,4 +51,22 @@ RSpec.describe ExperimentSubject, type: :model do
       end
     end
   end
+
+  describe '.valid_subject?' do
+    subject(:valid_subject?) { described_class.valid_subject?(subject_class.new) }
+
+    context 'when passing a Group, Namespace, User or Project' do
+      [Group, Namespace, User, Project].each do |subject_class|
+        let(:subject_class) { subject_class }
+
+        it { is_expected.to be(true) }
+      end
+    end
+
+    context 'when passing another object' do
+      let(:subject_class) { Issue }
+
+      it { is_expected.to be(false) }
+    end
+  end
 end