diff --git a/core/tests/Drupal/Tests/Core/Datetime/DateTest.php b/core/tests/Drupal/Tests/Core/Datetime/DateTest.php
index c717820..303d09d 100644
--- a/core/tests/Drupal/Tests/Core/Datetime/DateTest.php
+++ b/core/tests/Drupal/Tests/Core/Datetime/DateTest.php
@@ -47,7 +47,12 @@ class DateTest extends UnitTestCase {
 
   protected function setUp() {
     parent::setUp();
+
+    $entity_storage = $this->getMock('Drupal\Core\Entity\EntityStorageInterface');
+
     $this->entityManager = $this->getMock('Drupal\Core\Entity\EntityManagerInterface');
+    $this->entityManager->expects($this->once())->method('getStorage')->with('date_format')->willReturn($entity_storage);
+
     $this->languageManager = $this->getMock('Drupal\Core\Language\LanguageManagerInterface');
     $this->stringTranslation = $this->getMock('Drupal\Core\StringTranslation\TranslationInterface');