ITT: Laravel 5.1+ support.

Author: dmitry-ivanov

src/Asserts/ScheduleAsserts.php

@@ -31,8 +31,10 @@ protected function seeInSchedule($command, $expression, $runInBackground = false
         $expression = $this->normalizeScheduleExpression(clone $event, $expression);
         $this->assertEquals($expression, $event->expression, $message);
 
-        $message = "Failed asserting that command `{$command}` is scheduled with the same `run in background` mode.";
-        $this->assertEquals($runInBackground, $event->runInBackground, $message);
+        if (isset($event->runInBackground)) {
+            $message = "Failed asserting that command `{$command}` is scheduled with the same `run in background` mode.";
+            $this->assertEquals($runInBackground, $event->runInBackground, $message);
+        }
     }
 
     protected function dontSeeInSchedule($command)