Add unit test for Notification Resolver

tests/Unit/Resolver/Notification/NotificationResolverTest.php

@@ -0,0 +1,36 @@
+<?php
+
+/*
+ * This file has been created by developers from BitBag.
+ * Feel free to contact us once you face any issues or want to start
+ * You can find more information about us on https://bitbag.io and write us
+ * an email on [email protected].
+ */
+
+declare(strict_types=1);
+
+namespace Tests\BitBag\SyliusAdyenPlugin\Unit\Resolver\Notification;
+
+use BitBag\SyliusAdyenPlugin\Exception\NotificationItemsEmptyException;
+use BitBag\SyliusAdyenPlugin\Resolver\Notification\NotificationResolver;
+use PHPUnit\Framework\TestCase;
+use Psr\Log\NullLogger;
+use Symfony\Component\Serializer\Normalizer\DenormalizerInterface;
+use Symfony\Component\Validator\Validator\ValidatorInterface;
+use Tests\BitBag\SyliusAdyenPlugin\Unit\Mock\RequestMother;
+
+final class NotificationResolverTest extends TestCase
+{
+    public function testUndefinedNotificationItemsRequestIsHandledProperly(): void
+    {
+        $resolver = new NotificationResolver(
+            $this->createMock(DenormalizerInterface::class),
+            $this->createMock(ValidatorInterface::class),
+            new NullLogger(),
+        );
+
+        $this->expectException(NotificationItemsEmptyException::class);
+
+        $resolver->resolve('dummy-payment-code', RequestMother::createDummy());
+    }
+}