Merge pull request #43 from prolic/null_payload

allow null in payload

src/Messaging/MessageDataAssertion.php

@@ -86,7 +86,7 @@ private static function assertSubPayload($payload)
             return;
         }
 
-        Assertion::scalar($payload, 'payload must only contain arrays and scalar values');
+        Assertion::nullOrscalar($payload, 'payload must only contain arrays and scalar values');
     }
 
     /**

tests/Messaging/MessageDataAssertionTest.php

@@ -28,7 +28,7 @@ final class MessageDataAssertionTest extends \PHPUnit_Framework_TestCase
      */
     public function it_asserts_message_data_returned_by_the_no_op_message_converter()
     {
-        $testAssertions = new DoSomething(['test' => 'assertions']);
+        $testAssertions = new DoSomething(['test' => 'assertions', ['null' => null]]);
 
         $messageConverter = new NoOpMessageConverter();