Allow customizing the reimbursement mailer class

core/app/models/spree/reimbursement.rb

@@ -162,7 +162,7 @@ def validate_return_items_belong_to_same_order
  end
 
  def send_reimbursement_email
- Spree::ReimbursementMailer.reimbursement_email(id).deliver_later
+ Spree::Config.reimbursement_mailer_class.reimbursement_email(id).deliver_later
  end
 
  # If there are multiple different reimbursement types for a single

core/lib/spree/app_configuration.rb

@@ -316,6 +316,14 @@ def default_pricing_options
  # signature as Spree::PromotionCodeBatchMailer.promotion_code_batch_finished.
  class_name_attribute :promotion_code_batch_mailer_class, default: 'Spree::PromotionCodeBatchMailer'
 
+ # Allows providing your own Mailer for reimbursement mailer.
+ #
+ # @!attribute [rw] reimbursement_mailer_class
+ # @return [ActionMailer::Base] an object that responds to "reimbursement_email"
+ # (e.g. an ActionMailer with a "reimbursement_email" method) with the same
+ # signature as Spree::ReimbursementMailer.reimbursement_email.
+ class_name_attribute :reimbursement_mailer_class, default: 'Spree::ReimbursementMailer'
+
  # Allows providing your own Mailer for shipped cartons.
  #
  # @!attribute [rw] carton_shipped_email_class

core/lib/spree/mailer_previews/reimbursement_preview.rb

@@ -6,7 +6,7 @@ class ReimbursementPreview < ActionMailer::Preview
  def reimbursement
  reimbursement = Reimbursement.last
  raise "Your database needs at least one Reimbursement to render this preview" unless reimbursement
- ReimbursementMailer.reimbursement_email(reimbursement)
+ Spree::Config.reimbursement_mailer_class.reimbursement_email(reimbursement)
  end
  end
  end