Setup experiment in Pipeline Editor controller

app/controllers/projects/ci/pipeline_editor_controller.rb

@@ -2,6 +2,7 @@
 
 class Projects::Ci::PipelineEditorController < Projects::ApplicationController
   before_action :check_can_collaborate!
+  before_action :setup_walkthrough_experiment, only: :show
   before_action do
     push_frontend_feature_flag(:schema_linting, @project, default_enabled: :yaml)
   end
@@ -16,4 +17,10 @@ class Projects::Ci::PipelineEditorController < Projects::ApplicationController
   def check_can_collaborate!
     render_404 unless can_collaborate_with_project?(@project)
   end
+
+  def setup_walkthrough_experiment
+    experiment(:pipeline_editor_walkthrough, actor: current_user) do |e|
+      e.candidate {}
+    end
+  end
 end

config/feature_flags/experiment/pipeline_editor_walkthrough.yml

+---
+name: pipeline_editor_walkthrough
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/73050
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/345558
+milestone: '14.5'
+type: experiment
+group: group::activation
+default_enabled: false

spec/controllers/projects/ci/pipeline_editor_controller_spec.rb

@@ -6,6 +6,8 @@ RSpec.describe Projects::Ci::PipelineEditorController do
   let_it_be(:project) { create(:project, :repository) }
   let_it_be(:user) { create(:user) }
 
+  subject(:show_request) { get :show, params: { namespace_id: project.namespace, project_id: project } }
+
   before do
     sign_in(user)
   end
@@ -14,8 +16,7 @@ RSpec.describe Projects::Ci::PipelineEditorController do
     context 'with enough privileges' do
       before do
         project.add_developer(user)
-
-        get :show, params: { namespace_id: project.namespace, project_id: project }
+        show_request
       end
 
       it { expect(response).to have_gitlab_http_status(:ok) }
@@ -28,13 +29,27 @@ RSpec.describe Projects::Ci::PipelineEditorController do
     context 'without enough privileges' do
       before do
         project.add_reporter(user)
-
-        get :show, params: { namespace_id: project.namespace, project_id: project }
+        show_request
       end
 
       it 'responds with 404' do
         expect(response).to have_gitlab_http_status(:not_found)
       end
     end
+
+    describe 'pipeline_editor_walkthrough experiment' do
+      before do
+        project.add_developer(user)
+      end
+
+      it 'tracks the assignment', :experiment do
+        expect(experiment(:pipeline_editor_walkthrough))
+          .to track(:assignment)
+          .with_context(actor: user)
+          .on_next_instance
+
+        show_request
+      end
+    end
   end
 end