Don't block new post notifications by one paused during sending [MAILPOET-1609]

lib/Newsletter/Scheduler/Scheduler.php

@@ -8,6 +8,7 @@ use MailPoet\Models\Newsletter;
 use MailPoet\Models\NewsletterOption;
 use MailPoet\Models\NewsletterOptionField;
 use MailPoet\Models\NewsletterPost;
+use MailPoet\Models\ScheduledTask;
 use MailPoet\Models\SendingQueue;
 use MailPoet\Tasks\Sending as SendingTask;
 use MailPoet\WP\Functions as WPFunctions;
@@ -129,9 +130,21 @@ class Scheduler {
   }
 
   static function createPostNotificationSendingTask($newsletter) {
-    $existing_notification_history = Newsletter::where('parent_id', $newsletter->id)
+    $existing_notification_history = Newsletter::table_alias('newsletters')
-      ->where('type', Newsletter::TYPE_NOTIFICATION_HISTORY)
+      ->where('newsletters.parent_id', $newsletter->id)
-      ->where('status', Newsletter::STATUS_SENDING)
+      ->where('newsletters.type', Newsletter::TYPE_NOTIFICATION_HISTORY)
+      ->where('newsletters.status', Newsletter::STATUS_SENDING)
+      ->join(
+        MP_SENDING_QUEUES_TABLE,
+        'queues.newsletter_id = newsletters.id',
+        'queues'
+      )
+      ->join(
+        MP_SCHEDULED_TASKS_TABLE,
+        'queues.task_id = tasks.id',
+        'tasks'
+      )
+      ->whereNotEqual('tasks.status', ScheduledTask::STATUS_PAUSED)
       ->findOne();
     if($existing_notification_history) {
       return;

tests/integration/Newsletter/Scheduler/SchedulerTest.php

@@ -94,6 +94,28 @@ class SchedulerTest extends \MailPoetTest {
     expect(SendingQueue::findMany())->count(1);
   }
 
+  function testItCreatesPostNotificationSendingTaskIfAPausedNotificationExists() {
+    $newsletter = $this->_createNewsletter();
+    $newsletter->schedule = '* 5 * * *';
+
+    // new queue record should be created
+    $queue_to_be_paused = Scheduler::createPostNotificationSendingTask($newsletter);
+    $queue_to_be_paused->task()->pause();
+
+    // another queue record should be created because the first one was paused
+    $newsletter->schedule = '* 10 * * *'; // different time to not clash with the first queue
+    $queue = Scheduler::createPostNotificationSendingTask($newsletter);
+    expect(SendingQueue::findMany())->count(2);
+    expect($queue->newsletter_id)->equals($newsletter->id);
+    expect($queue->status)->equals(SendingQueue::STATUS_SCHEDULED);
+    expect($queue->scheduled_at)->equals(Scheduler::getNextRunDate('* 10 * * *'));
+    expect($queue->priority)->equals(SendingQueue::PRIORITY_MEDIUM);
+
+    // duplicate queue record should not be created
+    Scheduler::createPostNotificationSendingTask($newsletter);
+    expect(SendingQueue::findMany())->count(2);
+  }
+
   function testItDoesNotCreateDuplicateWelcomeNotificationSendingTasks() {
     $newsletter = (object)array(
       'id' => 1,
@@ -728,6 +750,11 @@ class SchedulerTest extends \MailPoetTest {
     $notification_history->parent_id = $newsletter->id;
     $notification_history->save();
 
+    $sending_task = SendingTask::create();
+    $sending_task->newsletter_id = $notification_history->id;
+    $sending_task->status = SendingQueue::STATUS_SCHEDULED;
+    $sending_task->save();
+
     $post_data = array(
       'post_title' => 'title',
       'post_status' => 'publish',