Add Learn Gitlab menu to project sidebar refactor

In this commit we add the `Learn Gitlab` menu to the
new project sidebar refactor.

app/helpers/sidebars_helper.rb

@@ -35,7 +35,8 @@ module SidebarsHelper
   def project_sidebar_context_data(project, user)
     {
       current_user: user,
-      container: project
+      container: project,
+      learn_gitlab_experiment_enabled: learn_gitlab_experiment_enabled?(project)
     }
   end
 end

app/models/sidebars/projects/menus/learn_gitlab/menu.rb

+# frozen_string_literal: true
+
+module Sidebars
+  module Projects
+    module Menus
+      module LearnGitlab
+        class Menu < ::Sidebars::Menu
+          override :link
+          def link
+            project_learn_gitlab_path(context.project)
+          end
+
+          override :active_routes
+          def active_routes
+            { controller: :learn_gitlab }
+          end
+
+          override :title
+          def title
+            _('Learn GitLab')
+          end
+
+          override :extra_container_html_options
+          def nav_link_html_options
+            { class: 'home' }
+          end
+
+          override :sprite_icon
+          def sprite_icon
+            'home'
+          end
+
+          override :render?
+          def render?
+            context.learn_gitlab_experiment_enabled
+          end
+        end
+      end
+    end
+  end
+end

app/models/sidebars/projects/panel.rb

@@ -8,6 +8,7 @@ module Sidebars
         set_scope_menu(Sidebars::Projects::Menus::Scope::Menu.new(context))
 
         add_menu(Sidebars::Projects::Menus::ProjectOverview::Menu.new(context))
+        add_menu(Sidebars::Projects::Menus::LearnGitlab::Menu.new(context))
       end
 
       override :render_raw_menus_partial

app/views/layouts/nav/sidebar/_project_menus.html.haml

-- if project_nav_tab? :learn_gitlab
-  = nav_link(controller: :learn_gitlab, html_options: { class: 'home' }) do
-    = link_to project_learn_gitlab_path(@project) do
-      .nav-icon-container
-        = sprite_icon('home')
-      %span.nav-item-name
-        = _('Learn GitLab')
-
 - if project_nav_tab? :files
   = nav_link(controller: sidebar_repository_paths, unless: -> { current_path?('projects/graphs#charts') }) do
     = link_to project_tree_path(@project), class: 'shortcuts-tree', data: { qa_selector: "repository_link" } do

spec/models/sidebars/projects/menus/learn_gitlab/menu_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Sidebars::Projects::Menus::LearnGitlab::Menu do
+  let(:project) { build(:project) }
+  let(:experiment_enabled) { true }
+  let(:context) { Sidebars::Projects::Context.new(current_user: nil, container: project, learn_gitlab_experiment_enabled: experiment_enabled) }
+
+  subject { described_class.new(context) }
+
+  it 'does not contain any sub menu' do
+    expect(subject.instance_variable_get(:@items)).to be_empty
+  end
+
+  describe '#render?' do
+    context 'when learn gitlab experiment is enabled' do
+      it 'returns true' do
+        expect(subject.render?).to eq true
+      end
+    end
+
+    context 'when learn gitlab experiment is disabled' do
+      let(:experiment_enabled) { false }
+
+      it 'returns false' do
+        expect(subject.render?).to eq false
+      end
+    end
+  end
+end

spec/views/layouts/nav/sidebar/_project.html.haml_spec.rb

@@ -50,6 +50,16 @@ RSpec.describe 'layouts/nav/sidebar/_project' do
     end
   end
 
+  describe 'Learn GitLab' do
+    it 'has a link to the learn GitLab experiment' do
+      allow(view).to receive(:learn_gitlab_experiment_enabled?).and_return(true)
+
+      render
+
+      expect(rendered).to have_link('Learn GitLab', href: project_learn_gitlab_path(project))
+    end
+  end
+
   describe 'issue boards' do
     it 'has board tab' do
       render