Add authorization_type and payment_plan to payment link, hosted, and session requests

spec/checkout_sdk/payments/payment_plan_fields_spec.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+RSpec.describe 'authorization_type and payment_plan request fields' do
+  let(:payment_plan) do
+    plan = CheckoutSdk::Payments::PaymentPlan.new
+    plan.amount_variability = 'Fixed'
+    plan.name = 'Monthly subscription'
+    plan
+  end
+  let(:authorization_type) { 'Estimated' }
+
+  shared_examples 'supports authorization_type and payment_plan' do |klass|
+    it "#{klass} exposes authorization_type" do
+      obj = klass.new
+      obj.authorization_type = authorization_type
+      expect(obj.authorization_type).to eq(authorization_type)
+    end
+
+    it "#{klass} exposes payment_plan" do
+      obj = klass.new
+      obj.payment_plan = payment_plan
+      expect(obj.payment_plan).to eq(payment_plan)
+      expect(obj.payment_plan.amount_variability).to eq('Fixed')
+    end
+  end
+
+  include_examples 'supports authorization_type and payment_plan', CheckoutSdk::Payments::PaymentLink
+  include_examples 'supports authorization_type and payment_plan', CheckoutSdk::Payments::HostedPaymentsSession
+  include_examples 'supports authorization_type and payment_plan', CheckoutSdk::Payments::PaymentSessionsRequest
+end