Move more logic out of the view & back into the helper

Reduce the logic necessary for the view down to two helpers:

1. show_trial_status_widget?(group)
1. trial_status_widget_experiment_enabled?(group) ← has a side effect

Also fixed the `new_subscriptions_path` to use the root_group rather
than the group.

ee/app/helpers/trial_status_widget_helper.rb

@@ -12,4 +12,22 @@ module TrialStatusWidgetHelper
   def plan_title_for_group(group)
     group.gitlab_subscription&.plan_title
   end
+
+  def show_trial_status_widget?(group)
+    return false unless billing_plans_and_trials_available?
+
+    eligible_for_trial_status_widget?(group)
+  end
+
+  # Note: This method has a side-effect in that it records the given group as a
+  # participant in the experiment (if the experiment is active at all) in the
+  # `experiment_subjects` table.
+  def trial_status_widget_experiment_enabled?(group)
+    experiment_key = :show_trial_status_in_sidebar
+
+    # Record the top-level group as a Growth::Conversion experiment participant
+    record_experiment_group(experiment_key, group)
+
+    experiment_enabled?(experiment_key, subject: group)
+  end
 end

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

--# Return early if this app instance does not have namespace plans enabled
-- return unless billing_plans_and_trials_available?
 -# Only top-level groups can have trials & plans
 - root_group = group.root_ancestor
--# Return without rendering if the top-level group & current user are not
--# eligible to see the trial status widget
-- return unless eligible_for_trial_status_widget?(root_group)
-
--# Growth::Conversion experiment-related stuff...
-- experiment_key = :show_trial_status_in_sidebar
--# * Record the top-level group as a Growth::Conversion experiment participant
-- record_experiment_group(experiment_key, root_group)
--# * But return without rendering if the group is not receiving the candidate
--#   variant experience
-- return unless experiment_enabled?(experiment_key, subject: root_group)
+- return unless show_trial_status_widget?(root_group)
+- return unless trial_status_widget_experiment_enabled?(root_group)
 
 = nav_link do
   #js-trial-status-widget{ data: { container_id: 'trial-status-sidebar-widget',
@@ -26,6 +15,6 @@
     group_name: root_group.name,
     plan_name: plan_title_for_group(root_group),
     plans_href: group_billings_path(root_group),
-    purchase_href: new_subscriptions_path(namespace_id: group.id, plan_id: '2c92a0fc5a83f01d015aa6db83c45aac'),
+    purchase_href: new_subscriptions_path(namespace_id: root_group.id, plan_id: '2c92a0fc5a83f01d015aa6db83c45aac'),
     target_id: 'trial-status-sidebar-widget',
     trial_end_date: root_group.trial_ends_on } }

ee/spec/helpers/trial_status_widget_helper_spec.rb

@@ -69,4 +69,62 @@ RSpec.describe TrialStatusWidgetHelper do
       it { is_expected.to eq(title) }
     end
   end
+
+  describe '#show_trial_status_widget?' do
+    let(:group) { instance_double(Group) }
+
+    before do
+      allow(helper).to receive(:billing_plans_and_trials_available?).and_return(trials_available)
+      allow(helper).to receive(:eligible_for_trial_status_widget?).with(group).and_return(eligible_for_widget)
+    end
+
+    subject { helper.show_trial_status_widget?(group) }
+
+    where(:trials_available, :eligible_for_widget, :result) do
+      true  | true  | true
+      true  | false | false
+      false | true  | false
+      false | false | false
+    end
+
+    with_them do
+      it { is_expected.to eq(result) }
+    end
+  end
+
+  describe '#trial_status_widget_experiment_enabled?' do
+    let(:experiment_key) { :show_trial_status_in_sidebar }
+    let(:group) { instance_double(Group) }
+
+    before do
+      allow(helper).to receive(:experiment_enabled?).with(experiment_key, subject: group).and_return(experiment_enabled)
+      allow(helper).to receive(:record_experiment_group)
+    end
+
+    subject { helper.trial_status_widget_experiment_enabled?(group) }
+
+    context 'when the experiment is not enabled for the given group' do
+      let(:experiment_enabled) { false }
+
+      it { is_expected.to be_falsey }
+
+      it 'records the group as an experiment participant' do
+        expect(helper).to receive(:record_experiment_group).with(experiment_key, group)
+
+        subject
+      end
+    end
+
+    context 'when the experiment is enabled for the given group' do
+      let(:experiment_enabled) { true }
+
+      it { is_expected.to be_truthy }
+
+      it 'records the group as an experiment participant' do
+        expect(helper).to receive(:record_experiment_group).with(experiment_key, group)
+
+        subject
+      end
+    end
+  end
 end

ee/spec/views/layouts/nav/sidebar/_group.html.haml_spec.rb

@@ -12,19 +12,16 @@ RSpec.describe 'layouts/nav/sidebar/_group' do
   let(:user) { create(:user) }
 
   describe 'trial status widget', :aggregate_failures do
+    using RSpec::Parameterized::TableSyntax
+
     let!(:gitlab_subscription) { create(:gitlab_subscription, :active_trial, namespace: group) }
 
-    let(:trials_available) { false }
+    let(:show_widget) { false }
     let(:experiment_enabled) { false }
-    let(:eligible_for_widget) { false }
 
     before do
-      allow(view).to receive(:billing_plans_and_trials_available?).and_return(trials_available)
-      allow(view).to receive(:eligible_for_trial_status_widget?).and_return(eligible_for_widget)
-
-      allow(view).to receive(:record_experiment_group)
-      allow(view).to receive(:experiment_enabled?).and_return(experiment_enabled)
-
+      allow(view).to receive(:show_trial_status_widget?).and_return(show_widget)
+      allow(view).to receive(:trial_status_widget_experiment_enabled?).and_return(experiment_enabled)
       render
     end
 
@@ -51,30 +48,15 @@ RSpec.describe 'layouts/nav/sidebar/_group' do
       end
     end
 
-    context 'when billing plans & trials are not available' do
-      include_examples 'does not render'
+    where :show_widget, :experiment_enabled, :examples_to_include do
+      true  | true  | 'does render'
+      true  | false | 'does not render'
+      false | true  | 'does not render'
+      false | false | 'does not render'
     end
 
-    context 'when billing plans & trials are available' do
-      let(:trials_available) { true }
-
-      context 'but the group and/or user are not eligible to see the widget' do
-        include_examples 'does not render'
-      end
-
-      context 'and the group and/or user are eligible to see the widget' do
-        let(:eligible_for_widget) { true }
-
-        context 'but the experiment is not enabled for the group' do
-          include_examples 'does not render'
-        end
-
-        context 'and the experiment is enabled for the group' do
-          let(:experiment_enabled) { true }
-
-          include_examples 'does render'
-        end
-      end
+    with_them do
+      include_examples(params[:examples_to_include])
     end
   end