diff --git a/core/tests/Drupal/Tests/UnitTestCase.php b/core/tests/Drupal/Tests/UnitTestCase.php
index 22a0fdd555..500b263fa7 100644
--- a/core/tests/Drupal/Tests/UnitTestCase.php
+++ b/core/tests/Drupal/Tests/UnitTestCase.php
@@ -4,9 +4,12 @@
 
 use Drupal\Tests\Core\UnitTestCase as CoreUnitTestCase;
 
+@trigger_error('The '. __NAMESPACE__ . '\UnitTestCase is deprecated in Drupal 8.5.0 and will be removed before Drupal 9.0.0. Instead, use \Drupal\Tests\Core\UnitTestCase', E_USER_DEPRECATED);
+
 /**
  * Backwards compatible unit test case.
  *
- * @deprecated
+ * @deprecated in Drupal 8.5.0 and will be removed before Drupal 9.0.0.
+ * Use \Drupal\Tests\Core\UnitTestCase
  */
 abstract class UnitTestCase extends CoreUnitTestCase {}