Limit trial status widget experiment participants to group owners

- Check that the root group is in an active trial
- Check that the current user is allowed to administer the root group

ee/app/helpers/trial_status_widget_helper.rb

 # frozen_string_literal: true
 module TrialStatusWidgetHelper
-  def eligible_for_trial_status_widget_experiment?(group)
-    group.trial_active?
-  end
-
   def show_trial_status_widget?(group)
-    return false unless ::Gitlab::CurrentSettings.should_check_namespace_plan?
-    return false unless experiment_enabled?(:show_trial_status_in_sidebar, subject: group)
-
-    eligible_for_trial_status_widget_experiment?(group)
+    billing_plans_and_trials_available? &&
+      trial_status_widget_experiment_enabled?(group) &&
+      group.trial_active? &&
+      user_can_administer_group?(group)
   end
   def trial_days_remaining_in_words(group)
@@ -22,4 +18,18 @@ def trial_days_remaining_in_words(group)
       num_of_days
     ) % { plan: plan_title, num: num_of_days, en_dash: '–' }
   end
+
+  private
+
+  def billing_plans_and_trials_available?
+    ::Gitlab::CurrentSettings.should_check_namespace_plan?
+  end
+
+  def trial_status_widget_experiment_enabled?(group)
+    experiment_enabled?(:show_trial_status_in_sidebar, subject: group)
+  end
+
+  def user_can_administer_group?(group)
+    can?(current_user, :admin_namespace, group)
+  end
 end

ee/app/views/layouts/nav/sidebar/_group_trial_status_widget.html.haml

-- return unless show_trial_status_widget?(group)
+- root_group = group.root_ancestor
+- return unless show_trial_status_widget?(root_group)
 = nav_link do
-  #js-trial-status-widget{ data: { href: group_billings_path(group),
+  #js-trial-status-widget{ data: { href: group_billings_path(root_group),
     nav_icon_image_path: image_path('illustrations/golden_tanuki.svg'),
-    title: trial_days_remaining_in_words(group),
-    percentage_complete: group.trial_percentage_complete } }
+    title: trial_days_remaining_in_words(root_group),
+    percentage_complete: root_group.trial_percentage_complete } }

ee/spec/helpers/trial_status_widget_helper_spec.rb

@@ -3,64 +3,65 @@
 require 'spec_helper'
 RSpec.describe TrialStatusWidgetHelper do
-  let_it_be(:group) { build(:group) }
-  let!(:subscription) { build(:gitlab_subscription, :active_trial, namespace: group) }
-  describe '#eligible_for_trial_status_widget_experiment?' do
-    subject { helper.eligible_for_trial_status_widget_experiment?(group) }
-    context 'when group has an active trial' do
-      it { is_expected.to be_truthy }
-    end
-    context 'when group does not have an active trial' do
-      before do
-        allow(group).to receive(:trial_active?).and_return(false)
-      end
-      it { is_expected.to be_falsy }
+  describe '#show_trial_status_widget?' do
+    let_it_be(:user) { create(:user) }
+    let(:trials_available) { true }
+    let(:experiment_enabled) { true }
+    let(:trial_active) { true }
+    let(:user_can_admin_group) { true }
+    let(:group) { instance_double(Group, trial_active?: trial_active) }
+    before do
+      # current_user
+      allow(helper).to receive(:current_user).and_return(user)
+      # billing_plans_and_trials_available?
+      stub_application_setting(check_namespace_plan: trials_available)
+      # trial_status_widget_experiment_enabled?(group)
+      allow(helper).to receive(:experiment_enabled?).with(:show_trial_status_in_sidebar, subject: group).and_return(experiment_enabled)
+
+      # user_can_administer_group?(group)
+      allow(helper).to receive(:can?).and_call_original
+      allow(helper).to receive(:can?).with(user, :admin_namespace, group).and_return(user_can_admin_group)
     end
-  end
-  describe '#show_trial_status_widget?' do
-    let(:experiment_enabled) { true }
-    let(:eligible_for_experiment) { true }
-    before do
-      allow(helper).to receive(:experiment_enabled?).with(:show_trial_status_in_sidebar, subject: group).and_return(experiment_enabled)
-      allow(helper).to receive(:eligible_for_trial_status_widget_experiment?).and_return(eligible_for_experiment)
+    subject { helper.show_trial_status_widget?(group) }
+    context 'when all requirements are met for the widget to be shown' do
+      it { is_expected.to be_truthy }
     end
-    subject { helper.show_trial_status_widget?(group) }
-    context 'when the check_namespace_plan application setting is off' do
-      it { is_expected.to be_falsy }
+    context 'when the app is not configured for billing plans & trials' do
+      let(:trials_available) { false }
+      it { is_expected.to be_falsey }
     end
-    context 'when the check_namespace_plan application setting is on' do
-      before do
-        stub_application_setting(check_namespace_plan: true)
-      end
-      context 'and the experiment is enabled and the user is eligible for it' do
-        it { is_expected.to be_truthy }
-      end
-      context 'but the experiment is not enabled' do
-        let(:experiment_enabled) { false }
-        it { is_expected.to be_falsy }
-      end
-      context 'but the user is not eligible for the experiment' do
-        let(:eligible_for_experiment) { false }
-        it { is_expected.to be_falsy }
-      end
+    context 'when the experiment is not active or not enabled for the group' do
+      let(:experiment_enabled) { false }
+      it { is_expected.to be_falsey }
+    end
+    context 'when the group is not in an active trial' do
+      let(:trial_active) { false }
+      it { is_expected.to be_falsey }
+    end
+    context 'when the user is not an admin/owner of the group' do
+      let(:user_can_admin_group) { false }
+      it { is_expected.to be_falsey }
     end
   end
   describe '#trial_days_remaining_in_words' do
+    let_it_be(:group) { build(:group) }
+    let!(:subscription) { build(:gitlab_subscription, :active_trial, namespace: group) }
+
     subject { helper.trial_days_remaining_in_words(group) }
     context 'when there are 0 days remaining' do