fix: restore room occupancy lost to case-sensitive xml attribute lookup

tests/Form/RoomSelectTypeTest.php

@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Form;
+
+use App\Form\Model\RoomSelectionDto;
+use App\Form\RoomSelectType;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Form\Forms;
+
+class RoomSelectTypeTest extends TestCase
+{
+    /**
+     * @param array<string, int> $expectedChoices
+     */
+    #[DataProvider('quantityChoiceProvider')]
+    public function testQuantityChoicesFollowAvailability(int $maxQuantity, array $expectedChoices): void
+    {
+        $data = new RoomSelectionDto();
+        $data->id = 95;
+        $data->maxQuantity = $maxQuantity;
+
+        $form = Forms::createFormFactory()->create(RoomSelectType::class, $data);
+
+        $this->assertSame($expectedChoices, $form->get('quantity')->getConfig()->getOption('choices'));
+    }
+
+    /**
+     * @return iterable<string, array{int, array<string, int>}>
+     */
+    public static function quantityChoiceProvider(): iterable
+    {
+        yield 'available rooms are selectable' => [2, ['-' => 0, '1' => 1, '2' => 2]];
+        // range(1, 0) would return [1, 0], offering a bookable "1" for a room with no availability.
+        yield 'no availability offers only the placeholder' => [0, ['-' => 0]];
+    }
+}