diff --git a/core/tests/test_celery_tasks.py b/core/tests/test_celery_tasks.py
index f4011843..dd0e6d15 100644
--- a/core/tests/test_celery_tasks.py
+++ b/core/tests/test_celery_tasks.py
@@ -1,6 +1,12 @@
+from datetime import timedelta
+
+from django.conf import settings
+from django.utils import timezone
 from rest_framework.test import APITestCase
 
 from core import celery_tasks
+from mail.enums import ReplyStatusEnum
+from mail.models import Mail
 
 
 class FlagsUpdateTest(APITestCase):
@@ -10,3 +16,14 @@ def test_debug_add(self):
 
     def test_debug_exception(self):
         self.assertRaises(Exception, celery_tasks.debug_exception)
+
+    def test_debug_count_mail(self):
+        sent_at = timezone.now() - timedelta(seconds=settings.EMAIL_AWAITING_REPLY_TIME)
+        Mail.objects.create(
+            edi_filename="filename",
+            edi_data="1\\fileHeader\\CHIEF\\SPIRE\\",
+            status=ReplyStatusEnum.PENDING,
+            sent_at=sent_at,
+        )
+        res = celery_tasks.debug_count_mail()
+        assert res == 1