diff --git a/lib/Db/MailAccount.php b/lib/Db/MailAccount.php
index 3744b1414a..c7470eda44 100644
--- a/lib/Db/MailAccount.php
+++ b/lib/Db/MailAccount.php
@@ -65,7 +65,7 @@
  * @method string getEditorMode()
  * @method void setEditorMode(string $editorMode)
  * @method int|null getProvisioningId()
- * @method void setProvisioningId(int $provisioningId)
+ * @method void setProvisioningId(int|null $provisioningId)
  * @method int getOrder()
  * @method void setOrder(int $order)
  * @method bool|null getShowSubscribedOnly()
diff --git a/tests/Integration/Db/MailAccountMapperTest.php b/tests/Integration/Db/MailAccountMapperTest.php
index ab78297db8..322432b0c0 100644
--- a/tests/Integration/Db/MailAccountMapperTest.php
+++ b/tests/Integration/Db/MailAccountMapperTest.php
@@ -28,10 +28,13 @@
 use OC;
 use OCA\Mail\Db\MailAccount;
 use OCA\Mail\Db\MailAccountMapper;
+use OCP\AppFramework\Db\DoesNotExistException;
 use OCP\IDBConnection;
+use function random_int;
 
 /**
  * @group DB
+ * @covers \OCA\Mail\Db\MailAccountMapper
  */
 class MailAccountMapperTest extends TestCase {
 	use DatabaseTransaction;
@@ -106,4 +109,14 @@ public function testSave() {
 		$this->assertNotNull($b->getId());
 		$this->assertEquals($b->getId(), $c->getId());
 	}
+
+	public function testDeleteProvisionedOrphans(): void {
+		$this->account->setProvisioningId(random_int(1, 10000));
+		$this->mapper->insert($this->account);
+
+		$this->mapper->deleteProvisionedOrphanAccounts();
+
+		$this->expectException(DoesNotExistException::class);
+		$this->mapper->findById($this->account->getId());
+	}
 }