diff --git a/tests/Unit/EventPaymentModuleRegistryTest.php b/tests/Unit/EventPaymentModuleRegistryTest.php
index 13dc5c4..a038d0f 100644
--- a/tests/Unit/EventPaymentModuleRegistryTest.php
+++ b/tests/Unit/EventPaymentModuleRegistryTest.php
@@ -50,10 +50,15 @@ class EventPaymentModuleRegistryTest extends TestCase
         $this->assertTrue($module->isConfigurationComplete(['iban' => 'DE123', 'account_owner' => 'Kasse']));
     }
 
-    public function test_existing_modules_have_no_participant_options(): void
+    public function test_participant_options_per_module(): void
     {
+        // Überweisung: keine payer-seitigen Eingaben.
         $this->assertSame([], (new AccountTransferPaymentModule())->getParticipantOptions());
-        $this->assertSame([], (new UndefinedPaymentModule())->getParticipantOptions());
+
+        // Sonstiges: exemplarische Teilnehmer-Eingaben (Betrag + Passend-Checkbox).
+        $undefined = (new UndefinedPaymentModule())->getParticipantOptions();
+        $this->assertSame(['amount_brought', 'has_exact_amount'], array_column($undefined, 'name'));
+        $this->assertSame('checkbox', $undefined[1]['type']);
     }
 
     public function test_participant_option_helpers(): void