feat: expose hotel cost unit and iso country code via the api

The Teamer app groups hotels by cost unit and renders a flag per
destination, and cannot derive either from what /api/hotels returns
today.

costUnit is the raw kostenstelle and stays a string: only 281 of 1931
hotels carry one and some hold a space-separated list such as "84 85".

countryCode goes through CountryCodeMapper, whose table is part of the
API contract: BusPro's land column mixes ISO-2, ISO-3 and European
vehicle registration codes for the same country, and a wrong entry
mislabels a destination's flag silently. An unmappable token is null and
warns on the bpn channel, never a guess. country itself is untouched --
it remains the join key into /api/countries[].token.

Co-Authored-By: Claude Opus 5 <[email protected]>

tests/BusProNet/XmlLoader/HotelLoaderTest.php

@@ -5,10 +5,14 @@ declare(strict_types=1);
 namespace App\Tests\BusProNet\XmlLoader;
 
 use App\BusProNet\Model\Travel;
+use App\BusProNet\Utility\CountryCodeMapper;
+use App\BusProNet\XmlCrawlerFactory;
 use App\BusProNet\XmlLoader\HotelLoader;
 use League\Flysystem\FilesystemOperator;
 use PHPUnit\Framework\TestCase;
+use Psr\Log\NullLogger;
 use Symfony\Component\Cache\Adapter\ArrayAdapter;
+use Symfony\Component\DomCrawler\Crawler;
 
 class HotelLoaderTest extends TestCase
 {
@@ -19,7 +23,7 @@ class HotelLoaderTest extends TestCase
             ->expects($this->never())
             ->method('read');
 
-        $loader = new HotelLoader(new ArrayAdapter(), $filesystem);
+        $loader = $this->createLoader($filesystem);
         $travel = new Travel();
         $travel->hotelId = null;
         $travel->hotel = null;
@@ -28,4 +32,64 @@ class HotelLoaderTest extends TestCase
 
         $this->assertNull($travel->hotel);
     }
+
+    public function testParseXmlMapsCostUnitAndCountryCode(): void
+    {
+        $hotel = $this->createLoader()->parseXml($this->hotelNode(
+            '<kostenstelle>83</kostenstelle><land>CH</land>'
+        ));
+
+        $this->assertSame('83', $hotel->costUnit);
+        $this->assertSame('CH', $hotel->country, 'the raw token is the join key and must not be rewritten');
+        $this->assertSame('ch', $hotel->countryCode);
+    }
+
+    public function testParseXmlKeepsAListOfCostUnitsAsAString(): void
+    {
+        $hotel = $this->createLoader()->parseXml($this->hotelNode(
+            '<kostenstelle>84 85</kostenstelle><land>D</land>'
+        ));
+
+        $this->assertSame('84 85', $hotel->costUnit);
+    }
+
+    public function testParseXmlLeavesCostUnitNullWhenAbsent(): void
+    {
+        $hotel = $this->createLoader()->parseXml($this->hotelNode('<land>D</land>'));
+
+        $this->assertNull($hotel->costUnit);
+        $this->assertSame('de', $hotel->countryCode);
+    }
+
+    public function testParseXmlLeavesBothCountryFieldsNullWhenLandIsAbsent(): void
+    {
+        $hotel = $this->createLoader()->parseXml($this->hotelNode('<name>Ohne Land</name>'));
+
+        $this->assertNull($hotel->country);
+        $this->assertNull($hotel->countryCode);
+    }
+
+    public function testParseXmlLeavesCountryCodeNullForAnUnmappableToken(): void
+    {
+        $hotel = $this->createLoader()->parseXml($this->hotelNode('<land>XX</land>'));
+
+        $this->assertSame('XX', $hotel->country);
+        $this->assertNull($hotel->countryCode, 'an unknown token must never be guessed into a code');
+    }
+
+    private function hotelNode(string $children): Crawler
+    {
+        $xml = sprintf('<hotels><hotel idbuspro="1" code="TEST">%s</hotel></hotels>', $children);
+
+        return XmlCrawlerFactory::create($xml)->filterXPath('//hotels/hotel');
+    }
+
+    private function createLoader(?FilesystemOperator $filesystem = null): HotelLoader
+    {
+        return new HotelLoader(
+            new CountryCodeMapper(new NullLogger()),
+            new ArrayAdapter(),
+            $filesystem ?? $this->createStub(FilesystemOperator::class),
+        );
+    }
 }