Support inline mode for dispatcher

We just need to define a condition for all work to be finished. This
comes handy in tests.

Author: rosa

lib/solid_queue/dispatcher.rb

@@ -51,6 +51,10 @@ def unload_recurring_schedule
         recurring_schedule.unload_tasks
       end
 
+      def all_work_completed?
+        SolidQueue::ScheduledExecution.none? && recurring_schedule.empty?
+      end
+
       def set_procline
         procline "waiting"
       end

lib/solid_queue/dispatcher/recurring_schedule.rb

@@ -11,6 +11,10 @@ def initialize(tasks)
       @scheduled_tasks = Concurrent::Hash.new
     end
 
+    def empty?
+      configured_tasks.empty?
+    end
+
     def load_tasks
       configured_tasks.each do |task|
         load_task(task)