diff --git a/core/tests/Drupal/Tests/Core/Entity/ContentEntityBaseUnitTest.php b/core/tests/Drupal/Tests/Core/Entity/ContentEntityBaseUnitTest.php
index b75b20323b..b765af8a69 100644
--- a/core/tests/Drupal/Tests/Core/Entity/ContentEntityBaseUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/ContentEntityBaseUnitTest.php
@@ -10,7 +10,6 @@
 use Drupal\Core\TypedData\TypedDataManagerInterface;
 use Drupal\Tests\UnitTestCase;
 use Drupal\Core\Language\Language;
-use Symfony\Component\Validator\Validator\ValidatorInterface;
 
 /**
  * @coversDefaultClass \Drupal\Core\Entity\ContentEntityBase
@@ -328,7 +327,7 @@ public function testPreSaveRevision() {
    * @covers ::validate
    */
   public function testValidate() {
-    $validator = $this->getMock(ValidatorInterface::class);
+    $validator = $this->getMock('\Symfony\Component\Validator\ValidatorInterface');
     /** @var \Symfony\Component\Validator\ConstraintViolationList|\PHPUnit_Framework_MockObject_MockObject $empty_violation_list */
     $empty_violation_list = $this->getMockBuilder('\Symfony\Component\Validator\ConstraintViolationList')
       ->setMethods(NULL)
@@ -364,7 +363,7 @@ public function testValidate() {
    * @expectedExceptionMessage Entity validation was skipped.
    */
   public function testRequiredValidation() {
-    $validator = $this->getMock(ValidatorInterface::class);
+    $validator = $this->getMock('\Symfony\Component\Validator\ValidatorInterface');
     /** @var \Symfony\Component\Validator\ConstraintViolationList|\PHPUnit_Framework_MockObject_MockObject $empty_violation_list */
     $empty_violation_list = $this->getMockBuilder('\Symfony\Component\Validator\ConstraintViolationList')
       ->setMethods(NULL)