feat: turn search_trips into the website's travel search

tests/Chatbot/TravelPeriodsTest.php

@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Chatbot;
+
+use App\Chatbot\TravelPeriods;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Clock\MockClock;
+
+class TravelPeriodsTest extends TestCase
+{
+    private TravelPeriods $periods;
+
+    protected function setUp(): void
+    {
+        $this->periods = new TravelPeriods([
+            ['label' => 'Herbst', 'from' => '2026-09-01', 'to' => '2026-10-07'],
+            ['label' => 'Silvester', 'from' => '2026-12-26', 'to' => '2027-01-03'],
+            ['label' => '1 Januarwoche', 'from' => '2027-01-02', 'to' => '2027-01-09'],
+        ], new MockClock('2026-10-08 10:00:00'));
+    }
+
+    public function testFindsACurrentPeriodByLabelIgnoringCase(): void
+    {
+        $range = $this->periods->find(' silvester ');
+
+        self::assertSame('2026-12-26', $range['from']->format('Y-m-d'));
+        self::assertSame('2027-01-03', $range['to']->format('Y-m-d'));
+    }
+
+    public function testAPeriodWhoseEndHasPassedIsNoLongerOffered(): void
+    {
+        self::assertNull($this->periods->find('Herbst'));
+        self::assertSame(['Silvester', '1 Januarwoche'], $this->periods->labels());
+    }
+
+    public function testAnUnknownLabelIsNull(): void
+    {
+        self::assertNull($this->periods->find('Pfingsten'));
+    }
+}