fix: refuse implausible accommodation booking prices

tests/Form/Admin/Groups/AccommodationBookingTypeTest.php

@@ -109,6 +109,60 @@ class AccommodationBookingTypeTest extends TestCase
         self::assertCount(0, $this->validate($booking, ['Default']));
     }
 
+    /**
+     * The overflow this guards against reached production as an out-of-range write on
+     * total_price: every figure in the breakdown is multiplied by the pax count and the
+     * nights, so an implausible input for either produces an implausible total.
+     */
+    public function testADepartureBeforeTheArrivalIsRejected(): void
+    {
+        $booking = $this->bookingFor('2026-09-23', '2026-09-20', 30);
+
+        $violations = $this->validate($booking, ['Default']);
+
+        self::assertCount(1, $violations);
+        self::assertSame('dateTo', $violations[0]->getPropertyPath());
+    }
+
+    public function testAMistypedYearIsRejectedRatherThanPriced(): void
+    {
+        // 2226 instead of 2026 — one wrong digit, 200 years of running costs.
+        $booking = $this->bookingFor('2026-09-23', '2226-09-25', 30);
+
+        $violations = $this->validate($booking, ['Default']);
+
+        self::assertCount(1, $violations);
+        self::assertSame('dateTo', $violations[0]->getPropertyPath());
+    }
+
+    public function testAnImplausiblePaxCountIsRejected(): void
+    {
+        $booking = $this->bookingFor('2026-09-23', '2026-09-25', AccommodationBooking::MAX_PAX + 1);
+
+        $violations = $this->validate($booking, ['Default']);
+
+        self::assertCount(1, $violations);
+        self::assertSame('paxCount', $violations[0]->getPropertyPath());
+    }
+
+    public function testTheLargestBookingOnRecordStillPasses(): void
+    {
+        // 150 people for 18 nights: the ceilings must not get in the way of real business.
+        $booking = $this->bookingFor('2026-09-23', '2026-10-11', 150);
+
+        self::assertCount(0, $this->validate($booking, ['Default']));
+    }
+
+    private function bookingFor(string $dateFrom, string $dateTo, int $paxCount): AccommodationBooking
+    {
+        $booking = new AccommodationBooking();
+        $booking->setDateFrom(new \DateTimeImmutable($dateFrom));
+        $booking->setDateTo(new \DateTimeImmutable($dateTo));
+        $booking->setPaxCount($paxCount);
+
+        return $booking;
+    }
+
     /**
      * @return string[]
      */