Override model_name.human for PaymentMethod

Recently we started using model_name.human instead of the raw class name
when displaying the names of payment methods.

Unfortunately, if there isn't an i18n key for that specific payment
method, model_name.human will fall back to "Payment Method", which is
not at all helpful in distinguishing it.

This commit changes PaymentMethod.model_name to return a custom
ActiveModel::Name subclass, which will use exact matches for
translations but doesn't fall back to "Payment Method", and instead will
use the "humanized" class name if there is no key.

core/app/models/spree/payment_method.rb

@@ -37,6 +37,21 @@ class PaymentMethod < Spree::Base
 
  include Spree::Preferences::StaticallyConfigurable
 
+ # Custom ModelName#human implementation to ensure we don't refer to
+ # subclasses as just "PaymentMethod"
+ class ModelName < ActiveModel::Name
+ # Similar to ActiveModel::Name#human, but skips lookup_ancestors
+ def human(options = {})
+ defaults = [
+ i18n_key,
+ options[:default],
+ @human
+ ].compact
+ options = { scope: [:activerecord, :models], count: 1, default: defaults }.merge!(options.except(:default))
+ I18n.translate(defaults.shift, options)
+ end
+ end
+
  class << self
  def providers
  Spree::Deprecation.warn 'Spree::PaymentMethod.providers is deprecated and will be deleted in Solidus 3.0. ' \
@@ -66,6 +81,10 @@ def available(display_on = nil, store: nil)
  end
  end
 
+ def model_name
+ ModelName.new(self, Spree)
+ end
+
  def active?
  where(type: to_s, active: true).count > 0
  end

core/spec/models/spree/payment_method_spec.rb

@@ -354,4 +354,20 @@ def gateway_class
  expect(payment_method.credit).to eq 'credit'
  end
  end
+
+ describe 'model_name.human' do
+ context 'PaymentMethod itself' do
+ it "returns i18n value" do
+ expect(Spree::PaymentMethod.model_name.human).to eq('Payment Method')
+ end
+ end
+
+ context 'A subclass with no i18n key' do
+ let!(:klass) { stub_const("MyGem::SomeClass", Class.new(described_class)) }
+
+ it "returns default humanized value" do
+ expect(klass.model_name.human).to eq('Some class')
+ end
+ end
+ end
 end