diff --git a/core/tests/Drupal/Tests/Core/EntityReferenceSelection/EntityReferenceSelectionUnitTest.php b/core/tests/Drupal/Tests/Core/EntityReferenceSelection/EntityReferenceSelectionUnitTest.php
index 25d153f885..350c2c2a18 100644
--- a/core/tests/Drupal/Tests/Core/EntityReferenceSelection/EntityReferenceSelectionUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/EntityReferenceSelection/EntityReferenceSelectionUnitTest.php
@@ -11,27 +11,11 @@
  * @coversDefaultClass \Drupal\Core\Entity\EntityReferenceSelection\SelectionPluginBase
  *
  * @group entity_reference
+ * @group legacy
  */
 class EntityReferenceSelectionUnitTest extends UnitTestCase {
 
   /**
-   * Triggered errors.
-   *
-   * @var array
-   */
-  protected $errors = [];
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    parent::setUp();
-    set_error_handler(function($severity, $message, $file, $line, $context) {
-      $this->errors[] = compact('severity', 'message', 'file', 'line', 'context');
-    });
-  }
-
-  /**
    * Tests invalid default configuration.
    *
    * @covers ::defaultConfiguration
@@ -203,59 +187,14 @@ public function testSetConfigurationBcLevel() {
    *
    * @covers ::setConfiguration
    * @covers ::resolveBackwardCompatibilityConfiguration
+   * @expectedDeprecation "Providing settings under 'handler_settings' is deprecated and will be removed before 9.0.0. Move the settings in the root of the configuration array. See https://www.drupal.org/node/2870971."
    */
   public function testDeprecationErrorTriggering() {
-    $deprecation_message = "Providing settings under 'handler_settings' is deprecated and will be removed before 9.0.0. Move the settings in the root of the configuration array. See https://www.drupal.org/node/2870971.";
-
-    // Configuration with no BC level.
-    $config = ['setting1' => TRUE];
-    new TestSelection($config, 'test_selector', []);
-    // Check that deprecation error has not been triggered.
-    $this->assertNoError($deprecation_message, E_USER_DEPRECATED);
-
     // Configuration with BC level.
     $config = ['handler_settings' => ['setting1' => TRUE]];
     new TestSelection($config, 'test_selector', []);
-    // Check that deprecation error has been triggered.
-    $this->assertError($deprecation_message, E_USER_DEPRECATED);
-  }
-
-  /**
-   * Asserts that an error has been triggered.
-   *
-   * @param string $message
-   *   The error message.
-   * @param int $severity
-   *   The error severity.
-   */
-  protected function assertError($message, $severity) {
-    $assertion_message = "Error '$message' (severity $severity) was triggered.";
-    foreach ($this->errors as $error) {
-      if ($error['message'] === $message && $error['severity'] === $severity) {
-        $this->assertTrue(TRUE, $assertion_message);
-        return;
-      }
-    }
-    $this->fail($assertion_message);
-  }
-
-  /**
-   * Asserts that a specific error has not been triggered.
-   *
-   * @param string $message
-   *   The error message.
-   * @param int $severity
-   *   The error severity.
-   */
-  protected function assertNoError($message, $severity) {
-    $assertion_message = "Error '$message' (severity $severity) was not triggered.";
-    foreach ($this->errors as $error) {
-      if ($error['message'] === $message && $error['severity'] === $severity) {
-        $this->fail($assertion_message);
-        return;
-      }
-    }
-    $this->assertTrue(TRUE, $assertion_message);
+    // Ensure at least one assertion.
+    $this->assertTrue(TRUE);
   }
 
 }