Ensure payment_method_id cannot be null on sources

app/models/solidus_paypal_braintree/transaction_import.rb

@@ -27,6 +27,7 @@ def initialize(order, transaction)
     def source
       SolidusPaypalBraintree::Source.new nonce: transaction.nonce,
         payment_type: transaction.payment_type,
+        payment_method: transaction.payment_method,
         user: user
     end
 

db/migrate/20170505193712_add_null_constraint_to_sources.rb

@@ -0,0 +1,30 @@
+class AddNullConstraintToSources < ActiveRecord::Migration
+  def up
+    payments = Spree::Payment.arel_table
+    sources = SolidusPaypalBraintree::Source.arel_table
+    join_sources = payments.join(sources).on(
+      payments[:source_id].eq(sources[:id]).and(
+        payments[:source_type].eq("SolidusPaypalBraintree::Source")
+      ).and(
+        sources[:payment_method_id].eq(nil)
+      )
+    ).join_sources
+
+    count = Spree::Payment.joins(join_sources).count
+    Rails.logger.info("Updating #{count} problematic sources")
+
+    Spree::Payment.joins(join_sources).find_each do |payment|
+      Rails.logger.info("Updating source #{payment.source_id} with payment method id #{payment.payment_method_id}")
+      SolidusPaypalBraintree::Source.where(id: payment.source_id).update_all(payment_method_id: payment.payment_method_id)
+    end
+
+    # We use a foreign key constraint on the model,
+    # but it doesnt make sense to have this model exist without a payment method
+    # as two of its methods delegate to the payment method.
+    change_column_null(:solidus_paypal_braintree_sources, :payment_method_id, false)
+  end
+
+  def down
+    change_column_null(:solidus_paypal_braintree_sources, :payment_method_id, true)
+  end
+end

spec/models/solidus_paypal_braintree/gateway_spec.rb

@@ -4,7 +4,7 @@
 
 RSpec.describe SolidusPaypalBraintree::Gateway do
   let(:gateway) do
-    new_gateway
+    new_gateway.tap(&:save)
   end
 
   let(:braintree) { gateway.braintree }
@@ -15,7 +15,8 @@
     SolidusPaypalBraintree::Source.new(
       nonce: 'fake-valid-nonce',
       user: user,
-      payment_type: payment_type
+      payment_type: payment_type,
+      payment_method: gateway
     )
   end
 

spec/models/solidus_paypal_braintree/transaction_import_spec.rb

@@ -54,6 +54,10 @@
       expect(subject.payment_type).to eq 'ApplePayCard'
     end
 
+    it 'takes the payment method from the transaction' do
+      expect(subject.payment_method).to eq braintree_gateway
+    end
+
     context 'order has a user' do
       let(:user) { Spree.user_class.new }
       let(:order) { Spree::Order.new user: user }