Ensured default domain redirects cannot be edited through regular approach

module/Core/test/Domain/DomainServiceTest.php

@@ -15,6 +15,7 @@ use Shlinkio\Shlink\Core\Domain\Model\DomainItem;
 use Shlinkio\Shlink\Core\Domain\Repository\DomainRepositoryInterface;
 use Shlinkio\Shlink\Core\Entity\Domain;
 use Shlinkio\Shlink\Core\Exception\DomainNotFoundException;
+use Shlinkio\Shlink\Core\Exception\InvalidDomainException;
 use Shlinkio\Shlink\Core\Options\NotFoundRedirectOptions;
 use Shlinkio\Shlink\Rest\ApiKey\Model\ApiKeyMeta;
 use Shlinkio\Shlink\Rest\ApiKey\Model\RoleDefinition;
@@ -213,4 +214,15 @@ class DomainServiceTest extends TestCase
         yield 'domain not found and author API key' => [null, $authorApiKey];
         yield 'domain found and author API key' => [$domain, $authorApiKey];
     }
+
+    /** @test */
+    public function anExceptionIsThrowsWhenTryingToEditRedirectsForDefaultDomain(): void
+    {
+        $this->expectException(InvalidDomainException::class);
+        $this->expectExceptionMessage(
+            'You cannot configure default domain\'s redirects this way. Use the configuration or env vars.',
+        );
+
+        $this->domainService->configureNotFoundRedirects('default.com', NotFoundRedirects::withoutRedirects());
+    }
 }

module/Core/test/Exception/InvalidDomainExceptionTest.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ShlinkioTest\Shlink\Core\Exception;
+
+use PHPUnit\Framework\TestCase;
+use Shlinkio\Shlink\Core\Exception\InvalidDomainException;
+
+class InvalidDomainExceptionTest extends TestCase
+{
+    /** @test */
+    public function configuresTheExceptionAsExpected(): void
+    {
+        $e = InvalidDomainException::forDefaultDomainRedirects();
+        $expected = 'You cannot configure default domain\'s redirects this way. Use the configuration or env vars.';
+
+        self::assertEquals($expected, $e->getMessage());
+        self::assertEquals($expected, $e->getDetail());
+        self::assertEquals('Invalid domain', $e->getTitle());
+        self::assertEquals('INVALID_DOMAIN', $e->getType());
+        self::assertEquals(400, $e->getStatus());
+    }
+}