Strip leading and trailing whitespace from code on assignment instead of before validation

Co-authored-by: Maikel <maikel@email.org.au>

app/models/voucher.rb

@@ -10,12 +10,14 @@ class Voucher < ApplicationRecord
            class_name: 'Spree::Adjustment',
            dependent: :nullify
 
-  before_validation :strip_code
-
   validates :code, length: { maximum: STRING_COLUMN_LIMIT },
                    presence: true, uniqueness: { scope: :enterprise_id }
   validates :amount, presence: true, numericality: { greater_than: 0 }
 
+  def code=(value)
+    super(value.to_s.strip)
+  end
+
   def display_value
     Spree::Money.new(amount)
   end
@@ -46,10 +48,4 @@ class Voucher < ApplicationRecord
   def compute_amount(order)
     -amount.clamp(0, order.pre_discount_total)
   end
-
-  private
-
-  def strip_code
-    code.strip! if code.present?
-  end
 end

spec/models/voucher_spec.rb

@@ -10,10 +10,9 @@ describe Voucher do
     it { is_expected.to have_many(:adjustments) }
   end
 
-  context "before validation" do
-    it "removes leading and trailing whitespace from the code" do
+  describe '#code=' do
+    it "removes leading and trailing whitespace" do
       voucher = build(:voucher, code: "\r\n\t new_code \r\n\t")
-      voucher.valid?
 
       expect(voucher.code).to eq("new_code")
     end