Push feature flag to frontend

Signed-off-by: Angelo Gulina <agulina@gitlab.com>

config/feature_flags/development/saas_add_seats_button.yml

+---
+name: saas_add_seats_button
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/49242
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/291060
+milestone: '13.7'
+type: development
+group: group::purchase
+default_enabled: false

ee/app/controllers/groups/billings_controller.rb

@@ -7,6 +7,7 @@ class Groups::BillingsController < Groups::ApplicationController
   before_action only: [:index] do
     push_frontend_feature_flag(:api_billable_member_list)
     push_frontend_feature_flag(:saas_manual_renew_button)
+    push_frontend_feature_flag(:saas_add_seats_button)
   end
 
   layout 'group_settings'

ee/app/helpers/billing_plans_helper.rb

@@ -15,6 +15,7 @@ module BillingPlansHelper
     {
       namespace_id: group.id,
       namespace_name: group.name,
+      add_seats_href: add_seats_url(group),
       plan_upgrade_href: plan_upgrade_url(group, plan),
       plan_renew_href: plan_renew_url(group),
       customer_portal_url: "#{EE::SUBSCRIPTIONS_URL}/subscriptions",
@@ -96,6 +97,12 @@ module BillingPlansHelper
 
   private
 
+  def add_seats_url(group)
+    return unless group
+
+    "#{EE::SUBSCRIPTIONS_URL}/gitlab/namespaces/#{group.id}/extra_seats"
+  end
+
   def plan_purchase_url(group, plan)
     if use_new_purchase_flow?(group)
       new_subscriptions_path(plan_id: plan.id, namespace_id: group.id)

ee/spec/helpers/billing_plans_helper_spec.rb

@@ -13,15 +13,15 @@ RSpec.describe BillingPlansHelper do
 
     context 'when group and plan with ID present' do
       it 'returns data attributes' do
-        upgrade_href =
-          "#{EE::SUBSCRIPTIONS_URL}/gitlab/namespaces/#{group.id}/upgrade/#{plan.id}"
-        renew_href =
-          "#{EE::SUBSCRIPTIONS_URL}/gitlab/namespaces/#{group.id}/renew"
+        add_seats_href = "#{EE::SUBSCRIPTIONS_URL}/gitlab/namespaces/#{group.id}/extra_seats"
+        upgrade_href = "#{EE::SUBSCRIPTIONS_URL}/gitlab/namespaces/#{group.id}/upgrade/#{plan.id}"
+        renew_href = "#{EE::SUBSCRIPTIONS_URL}/gitlab/namespaces/#{group.id}/renew"
         billable_seats_href = helper.group_seat_usage_path(group)
 
         expect(helper.subscription_plan_data_attributes(group, plan))
           .to eq(namespace_id: group.id,
                  namespace_name: group.name,
+                 add_seats_href: add_seats_href,
                  plan_upgrade_href: upgrade_href,
                  plan_renew_href: renew_href,
                  customer_portal_url: customer_portal_url,
@@ -41,6 +41,7 @@ RSpec.describe BillingPlansHelper do
       let(:plan) { Hashie::Mash.new(id: nil) }
 
       it 'returns data attributes without upgrade href' do
+        add_seats_href = "#{EE::SUBSCRIPTIONS_URL}/gitlab/namespaces/#{group.id}/extra_seats"
         renew_href = "#{EE::SUBSCRIPTIONS_URL}/gitlab/namespaces/#{group.id}/renew"
         billable_seats_href = helper.group_seat_usage_path(group)
 
@@ -49,6 +50,7 @@ RSpec.describe BillingPlansHelper do
                  namespace_name: group.name,
                  customer_portal_url: customer_portal_url,
                  billable_seats_href: billable_seats_href,
+                 add_seats_href: add_seats_href,
                  plan_renew_href: renew_href,
                  plan_upgrade_href: nil)
       end