Issue #2994955 by andypost, mondrake: Followup to #2848952 - fix DatabaseLegacyTest::testDbMerge

core/tests/Drupal/KernelTests/Core/Database/DatabaseLegacyTest.php

@@ -4,6 +4,7 @@
 
 use Drupal\Core\Database\Query\Condition;
 use Drupal\Core\Database\Query\Delete;
+use Drupal\Core\Database\Query\Merge;
 use Drupal\Core\Database\Query\Update;
 use Drupal\Core\Database\Transaction;
 use Drupal\Core\Database\Database;
@@ -196,16 +197,7 @@ public function testDbCreateTable() {
    * @expectedDeprecation db_merge() is deprecated in Drupal 8.0.x and will be removed before Drupal 9.0.0. Instead, get a database connection injected into your service from the container and call merge() on it. For example, $injected_database->merge($table, $options). See https://www.drupal.org/node/2993033
    */
   public function testDbMerge() {
-    $num_records_before = (int) $this->connection->select('test_people')->countQuery()->execute()->fetchField();
-    $result = db_merge('test_people')
-      ->key('job', 'Presenter')
-      ->fields([
-        'age' => 31,
-        'name' => 'Tiffany',
-      ])
-      ->execute();
-    $num_records_after = (int) $this->connection->select('test_people')->countQuery()->execute()->fetchField();
-    $this->assertSame($num_records_before + 1, $num_records_after, 'Merge inserted properly.');
+    $this->assertInstanceOf(Merge::class, db_merge('test'));
   }
 
   /**