Paymill: Add support for void

Closes activemerchant#856.

CHANGELOG

@@ -3,6 +3,7 @@
 * Moneris: Add optional (off by default) verification_value support [duff]
 * Spreedly: Pass country with other address fields [hoenth]
 * SecureNet: Fix order of xml params [duff]
+* Paymill: Add support for void [duff]
 
 == Version 1.38.1 (September 16, 2013)
 

lib/active_merchant/billing/gateways/paymill.rb

@@ -57,6 +57,10 @@ def refund(money, authorization, options={})
         commit(:post, "refunds/#{transaction_id(authorization)}", post)
       end
 
+      def void(authorization, options={})
+        commit(:delete, "preauthorizations/#{preauth(authorization)}")
+      end
+
       def store(credit_card, options={})
         save_card(credit_card)
       end
@@ -97,9 +101,12 @@ def response_from(raw_response)
       end
 
       def authorization_from(parsed_response)
+        parsed_data = parsed_response['data']
+        return '' unless parsed_data.kind_of?(Hash)
+
         [
-          parsed_response['data']['id'],
-          parsed_response['data']['preauthorization'].try(:[], 'id')
+          parsed_data['id'],
+          parsed_data['preauthorization'].try(:[], 'id')
         ].join(";")
       end
 
@@ -158,6 +165,8 @@ def save_card_url
       end
 
       def post_data(params)
+        return nil unless params
+
         no_blanks = params.reject { |key, value| value.blank? }
         no_blanks.map { |key, value| "#{key}=#{CGI.escape(value.to_s)}" }.join("&")
       end

test/remote/gateways/remote_paymill_test.rb

@@ -41,7 +41,18 @@ def test_failed_capture
 
     assert capture_response = @gateway.capture(@amount, response.authorization)
     assert_failure capture_response
-    assert_equal 'Preauthorization has already been used', capture_response.message
+    assert_equal 'Transaction duplicate', capture_response.message
+  end
+
+  def test_successful_authorize_and_void
+    assert response = @gateway.authorize(@amount, @credit_card)
+    assert_success response
+    assert_equal 'Transaction approved', response.message
+    assert response.authorization
+
+    assert void_response = @gateway.void(response.authorization)
+    assert_success void_response
+    assert_equal 'Transaction approved', void_response.message
   end
 
   def test_successful_refund

test/unit/gateways/paymill_test.rb

@@ -67,6 +67,19 @@ def test_successful_authorize_and_capture
     assert_equal "Transaction approved", response.message
   end
 
+  def test_successful_authorize_and_void
+    @gateway.stubs(:raw_ssl_request).returns(successful_store_response, successful_authorize_response)
+
+    assert response = @gateway.authorize(@amount, @credit_card)
+    assert_success response
+
+    @gateway.expects(:raw_ssl_request).returns(successful_void_response)
+    response = @gateway.void(response.authorization)
+    assert_success response
+    assert response.test?
+    assert_equal "Transaction approved", response.message
+  end
+
   def test_failed_capture
     @gateway.stubs(:raw_ssl_request).returns(successful_store_response, successful_authorize_response)
     assert response = @gateway.authorize(@amount, @credit_card)
@@ -378,6 +391,15 @@ def successful_capture_response
     JSON
   end
 
+  def successful_void_response
+    MockResponse.succeeded <<-JSON
+      {
+          "data":[],
+          "mode":"test"
+      }
+    JSON
+  end
+
   def successful_refund_response
     MockResponse.succeeded <<-JSON
       {