Paypal Express gateway: Fix missing address

Calling PaypalExpressResponse#address when the response didn't contain
any address information was causing a dereference error:

  NoMethodError: undefined method `[]' for nil:NilClass

Closes activemerchant#628.

CHANGELOG

@@ -14,6 +14,7 @@
 * DataCash: Update test Mastercard number [jamesshipton]
 * DataCash: Update test response fixtures [jamesshipton]
 * Pin: Add Pin.js card token support [nagash]
+* PayPal Express gateway: Fix error when no address information is in response [pierre]
 
 == Version 1.31.1 (February 25, 2013)
 

lib/active_merchant/billing/gateways/paypal/paypal_express_response.rb

@@ -8,31 +8,36 @@ def email
       def info
         (@params['PayerInfo']||{})
       end
-
+
+      def details
+        (@params['PaymentDetails']||{})
+      end
+
       def name
         payer = (info['PayerName']||{})
         [payer['FirstName'], payer['MiddleName'], payer['LastName']].compact.join(' ')
       end
-      
+
       def token
         @params['Token']
       end
-      
+
       def payer_id
         info['PayerID']
       end
-      
+
       def payer_country
         info['PayerCountry']
       end
-
-      # PayPal returns a contact telephone number only if your Merchant account profile settings require that the buyer enter one.
+
+      # PayPal returns a contact telephone number only if your Merchant account
+      # profile settings require that the buyer enter one.
       def contact_phone
         @params['ContactPhone']
       end
-      
+
       def address
-        address = (@params['PaymentDetails']||{})['ShipToAddress']
+        address = (details['ShipToAddress']||{})
         {  'name'       => address['Name'],
            'company'    => info['PayerBusiness'],
            'address1'   => address['Street1'],
@@ -44,7 +49,7 @@ def address
            'phone'      => (contact_phone || address['Phone'])
         }
       end
-      
+
       def shipping
         shipping = (@params['UserSelectedOptions']||{})
         {  'amount'   => shipping['ShippingOptionAmount'],

test/unit/gateways/paypal_express_test.rb

@@ -100,7 +100,11 @@ def test_get_express_details
     assert shipping = response.shipping
     assert_equal '2.95', shipping['amount']
     assert_equal 'default', shipping['name']
+  end
 
+  def test_express_response_missing_address
+    response = PaypalExpressResponse.new(true, "ok")
+    assert_nil response.address['address1']
   end
 
   def test_authorization