Override model_name.human for PaymentMethod

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