Include default plan as being eligible for a trial

ee/app/models/ee/plan.rb

@@ -16,7 +16,7 @@ module EE
       PAID_HOSTED_PLANS = [BRONZE, SILVER, GOLD].freeze
       FREE_HOSTED_PLANS = [EARLY_ADOPTER].freeze
       EE_ALL_PLANS = (EE_DEFAULT_PLANS + PAID_HOSTED_PLANS + FREE_HOSTED_PLANS).freeze
-      PLANS_ELIGIBLE_FOR_TRIAL = [FREE, *FREE_HOSTED_PLANS].freeze
+      PLANS_ELIGIBLE_FOR_TRIAL = [*EE_DEFAULT_PLANS, *FREE_HOSTED_PLANS].freeze
 
       # This constant must keep ordered by tier.
       ALL_HOSTED_PLANS = (PAID_HOSTED_PLANS + FREE_HOSTED_PLANS).freeze

ee/spec/factories/gitlab_subscriptions.rb

@@ -24,6 +24,10 @@ FactoryBot.define do
       trial_ends_on { Date.today.advance(days: -1) }
     end
 
+    trait :default do
+      association :hosted_plan, factory: :default_plan
+    end
+
     trait :free do
       hosted_plan_id { nil }
     end

ee/spec/models/plan_spec.rb

@@ -22,4 +22,10 @@ RSpec.describe Plan do
       end
     end
   end
+
+  describe '::PLANS_ELIGIBLE_FOR_TRIAL' do
+    subject { ::Plan::PLANS_ELIGIBLE_FOR_TRIAL }
+
+    it { is_expected.to eq(%w[default free early_adopter]) }
+  end
 end