feat: special treatment of participants with age 0-2 (babies)

src/BusProNet/Constants.php

@@ -64,4 +64,8 @@ final class Constants
     // Payment type IDs for API
     public const PAYMENT_TYPE_ID_TRANSFER = 2;
     public const PAYMENT_TYPE_ID_DEBIT = 5;
+
+    // Baby room constraints
+    public const BABY_MAX_AGE = 2;
+    public const BABY_ROOM_CODE = 'Baby';
 }

src/Form/Model/ParticipantDto.php

@@ -78,7 +78,8 @@ class ParticipantDto
     public array $courses = [];
     public array $additionalServices = [];
 
-    #[Assert\NotNull(message: 'Bitte auswählen', groups: ['strict_required'])]
+    // Note: Ski pass validation is conditional - see ParticipantEditDto::validateSkiPassRequired()
+    // Babies (0-2 years) are exempt from ski pass requirement
     public ?Service $skiPass = null;
 
     public array $board = [];

src/Form/Model/ParticipantEditDto.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace App\Form\Model;
 
+use App\BusProNet\Constants;
 use App\Validator\Constraints as AppAssert;
 use Symfony\Component\Validator\Constraints as Assert;
 use Symfony\Component\Validator\Context\ExecutionContextInterface;
@@ -27,6 +28,39 @@ class ParticipantEditDto
     ) {
     }
 
+    /**
+     * Validates that ski pass is selected when required.
+     *
+     * Ski pass is required for all participants in create mode, EXCEPT for babies
+     * (participants aged 0-2 years at travel date). Babies don't qualify for any
+     * ski pass and the field is hidden for them.
+     *
+     * In edit mode, this validation is skipped as the ski pass is readonly.
+     *
+     * This validation only runs when strict_required group is active.
+     */
+    #[Assert\Callback(groups: ['strict_required'])]
+    public function validateSkiPassRequired(ExecutionContextInterface $context): void
+    {
+        // Skip validation in edit mode - ski pass is readonly
+        if (BookingDto::MODE_EDIT === $this->bookingContext->getMode()) {
+            return;
+        }
+
+        // Baby age exemption: skip validation for participants at or under BABY_MAX_AGE
+        $age = $this->participant->getAge($this->bookingContext->travel->dateFrom);
+        if (null !== $age && $age <= Constants::BABY_MAX_AGE) {
+            return;
+        }
+
+        // Ski pass is required for non-baby participants
+        if (null === $this->participant->skiPass) {
+            $context->buildViolation('Bitte auswählen')
+                ->atPath('participant.skiPass')
+                ->addViolation();
+        }
+    }
+
     /**
      * Validates that insurance is selected when required.
      *

src/Form/Service/Condition/BabyAgeCondition.php

@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Form\Service\Condition;
+
+use App\BusProNet\Constants;
+use App\Form\Model\BookingDto;
+use App\Form\Service\Contract\FieldConditionInterface;
+
+/**
+ * Condition that evaluates if a participant is at or under baby age (0-2 years).
+ *
+ * This condition checks if a participant's age at travel start date is at or under
+ * the BABY_MAX_AGE threshold (2 years). It's used to conditionally hide fields
+ * that are not applicable to babies, such as ski pass selection.
+ *
+ * Age is calculated at the travel start date, consistent with other age-dependent
+ * services in the system (insurance, ski pass, etc.).
+ */
+class BabyAgeCondition implements FieldConditionInterface
+{
+    /**
+     * Evaluates if the participant is at or under baby age.
+     *
+     * Calculates the participant's age at travel start date and checks if it's
+     * at or under BABY_MAX_AGE (2 years). Returns false if the participant has
+     * no date of birth set.
+     *
+     * @param BookingDto           $bookingDto       The current booking data
+     * @param int                  $participantIndex The index of the participant being evaluated
+     * @param array<string, mixed> $formData         Current form data (unused)
+     *
+     * @return bool True if the participant is at or under baby age, false otherwise
+     */
+    public function evaluate(BookingDto $bookingDto, int $participantIndex, array $formData): bool
+    {
+        $participant = $bookingDto->getParticipant($participantIndex);
+
+        if (null === $participant || null === $participant->dateOfBirth) {
+            return false;
+        }
+
+        $age = $participant->getAge($bookingDto->travel->dateFrom);
+
+        if (null === $age) {
+            return false;
+        }
+
+        return $age <= Constants::BABY_MAX_AGE;
+    }
+
+    /**
+     * Returns field names that affect baby age calculation.
+     *
+     * The condition depends on the participant's date of birth field.
+     * When this field changes, any conditions based on baby age should be re-evaluated.
+     *
+     * @return string[] Array containing 'dateOfBirth' field name
+     */
+    public function getDependentFields(): array
+    {
+        return ['dateOfBirth'];
+    }
+
+    /**
+     * Returns a human-readable description of the condition.
+     *
+     * @return string Description of the baby age condition
+     */
+    public function getDescription(): string
+    {
+        return sprintf('Participant is at or under baby age (%d years)', Constants::BABY_MAX_AGE);
+    }
+}

src/Form/Service/Condition/MultipleParticipantsCondition.php

@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Form\Service\Condition;
+
+use App\Form\Model\BookingDto;
+use App\Form\Service\Contract\FieldConditionInterface;
+
+/**
+ * Condition that checks if the booking has multiple participants.
+ *
+ * This is used to hide fields that are only relevant when there are
+ * multiple participants, such as the bulk insurance assignment option.
+ */
+class MultipleParticipantsCondition implements FieldConditionInterface
+{
+    /**
+     * Evaluates if the booking has more than one participant.
+     *
+     * @param BookingDto           $bookingDto       The current booking data
+     * @param int                  $participantIndex The index of the participant being evaluated (unused)
+     * @param array<string, mixed> $formData         Current form data (unused)
+     *
+     * @return bool True if the booking has 2+ participants, false otherwise
+     */
+    public function evaluate(BookingDto $bookingDto, int $participantIndex, array $formData): bool
+    {
+        return count($bookingDto->participants) > 1;
+    }
+
+    public function getDependentFields(): array
+    {
+        return [];
+    }
+
+    public function getDescription(): string
+    {
+        return 'Checks if the booking has multiple participants (2+)';
+    }
+}

src/Form/Service/CreateFieldStateProvider.php

@@ -8,12 +8,14 @@ use App\BusProNet\Utility\DirectionMapper;
 use App\Form\Service\Abstract\AbstractFieldStateProvider;
 use App\Form\Service\Condition\ApplicantCondition;
 use App\Form\Service\Condition\AuthenticatedUserPersonalDataCondition;
+use App\Form\Service\Condition\BabyAgeCondition;
 use App\Form\Service\Condition\BookingEligibilityCondition;
 use App\Form\Service\Condition\BulkInsuranceBookingCondition;
 use App\Form\Service\Condition\CompositeCondition;
 use App\Form\Service\Condition\DateOfBirthProvidedCondition;
 use App\Form\Service\Condition\FieldValueCondition;
 use App\Form\Service\Condition\FinalBookingOnlyCondition;
+use App\Form\Service\Condition\MultipleParticipantsCondition;
 use App\Form\Service\Condition\RentalSelectionCondition;
 use App\Form\Service\Condition\RoomSelectionCondition;
 use App\Form\Service\Condition\ServiceSubTypeCondition;
@@ -142,6 +144,9 @@ class CreateFieldStateProvider extends AbstractFieldStateProvider
         // Hide age-dependent fields when no date of birth is provided
         $dateOfBirthProvidedCondition = new DateOfBirthProvidedCondition();
 
+        // Baby age condition - hide ski pass for babies (0-2 years)
+        $babyAgeCondition = new BabyAgeCondition();
+
         // Age-dependent service fields are hidden until birth date is provided OR when participant is ineligible
         $this->fieldStateConditions['courses'] = [
             'hidden' => CompositeCondition::or(
@@ -157,11 +162,15 @@ class CreateFieldStateProvider extends AbstractFieldStateProvider
             ),
         ];
 
-        // Skipass field - hidden when participant is ineligible OR when no date of birth
+        // Skipass field - hidden when:
+        // - No date of birth provided
+        // - Participant is ineligible (no skipasses for their age)
+        // - Participant is baby age (0-2 years) - babies don't need ski passes
         $this->fieldStateConditions['skiPass'] = [
             'hidden' => CompositeCondition::or(
                 CompositeCondition::not($dateOfBirthProvidedCondition),
-                $bookingEligibilityCondition
+                $bookingEligibilityCondition,
+                $babyAgeCondition
             ),
         ];
 
@@ -184,11 +193,14 @@ class CreateFieldStateProvider extends AbstractFieldStateProvider
         // Bulk insurance booking conditions
         $bulkInsuranceBookingCondition = new BulkInsuranceBookingCondition();
 
-        // Show bulk insurance booking checkbox ONLY for applicant (index 0) and when insurance field is visible
+        // Show bulk insurance booking checkbox ONLY for applicant (index 0) when:
+        // - Date of birth is provided
+        // - There are multiple participants (bulk assignment is meaningless for single participant)
         $this->fieldStateConditions['bulkInsuranceBooking'] = [
             'hidden' => CompositeCondition::or(
                 CompositeCondition::not($dateOfBirthProvidedCondition), // Hide until date of birth provided
-                CompositeCondition::not(new ApplicantCondition()) // Hide for non-applicants
+                CompositeCondition::not(new ApplicantCondition()), // Hide for non-applicants
+                CompositeCondition::not(new MultipleParticipantsCondition()) // Hide when only one participant
             ),
         ];
 

src/Form/Service/ParticipantFieldOptionsProvider.php

@@ -16,7 +16,6 @@ use App\Form\Service\Factory\ParticipantRoomChoiceLoaderFactory;
 use App\Service\BookingPriceCalculatorService;
 use App\Service\InsuranceService;
 use App\Service\ServiceAvailabilityCalculator;
-use App\Validator\Constraints\RoomSelection;
 
 /**
  * Provides dynamic field options for participant form fields.
@@ -580,9 +579,9 @@ class ParticipantFieldOptionsProvider extends AbstractFieldOptionsProvider
                 return false;
             }
 
-            // Baby rooms only available for participants 2 years or younger
-            if (RoomSelection::BABY_ROOM_CODE === $room->code) {
-                return $age <= 2;
+            // Baby rooms only available for participants at or under BABY_MAX_AGE
+            if (Constants::BABY_ROOM_CODE === $room->code) {
+                return $age <= Constants::BABY_MAX_AGE;
             }
 
             // All other rooms available for all ages

src/Service/ParticipantEligibilityService.php

@@ -31,12 +31,15 @@ class ParticipantEligibilityService
      * Returns true when the participant can book services (at least one skipass available).
      * Returns false when the participant cannot book (no skipasses available for their age).
      *
+     * Baby age exemption: Participants aged 0-2 years (at travel date) are always eligible
+     * regardless of skipass availability, as babies don't require ski passes.
+     *
      * Results are cached per request to avoid redundant calculations.
      *
      * @param BookingDto $bookingDto       The current booking data
      * @param int        $participantIndex The index of the participant being evaluated
      *
-     * @return bool True if participant is eligible (has available skipasses)
+     * @return bool True if participant is eligible (has available skipasses or is baby age)
      */
     public function isParticipantEligible(BookingDto $bookingDto, int $participantIndex): bool
     {
@@ -54,7 +57,13 @@ class ParticipantEligibilityService
             $participantIndex
         );
 
-        return $this->eligibilityCache[$cacheKey] ??= (function () use ($bookingDto, $participantIndex) {
+        return $this->eligibilityCache[$cacheKey] ??= (function () use ($bookingDto, $participantIndex, $participant) {
+            // Baby age exemption: participants at or under BABY_MAX_AGE are always eligible
+            $age = $participant->getAge($bookingDto->travel->dateFrom);
+            if (null !== $age && $age <= Constants::BABY_MAX_AGE) {
+                return true;
+            }
+
             $allSkiPasses = $bookingDto->travel->getAdditionalServicesBySubTypes(Constants::TOKEN_SKI_PASS, true, true);
             $availableSkiPasses = array_filter(
                 $allSkiPasses,

src/Validator/Constraints/RoomSelection.php

@@ -9,8 +9,6 @@ use Symfony\Component\Validator\Constraint;
 #[\Attribute]
 class RoomSelection extends Constraint
 {
-    public const BABY_ROOM_CODE = 'Baby';
-
     public string $noRoomSelectedMessage = 'Bitte mindestens ein Zimmer/Bett auswählen';
     public string $onlyBabyRoomsMessage = 'Baby-Zimmer können nur in Kombination mit regulären Zimmern gebucht werden.';
 

src/Validator/Constraints/RoomSelectionValidator.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace App\Validator\Constraints;
 
+use App\BusProNet\Constants;
 use App\Form\Model\BookingDto;
 use Symfony\Component\Validator\Constraint;
 use Symfony\Component\Validator\ConstraintValidator;
@@ -50,14 +51,14 @@ class RoomSelectionValidator extends ConstraintValidator
                 continue;
             }
 
-            if (RoomSelection::BABY_ROOM_CODE === $room->code) {
+            if (Constants::BABY_ROOM_CODE === $room->code) {
                 $hasBabyRoom = true;
             } else {
                 $hasRegularRoom = true;
             }
         }
 
-        if ($hasBabyRoom && !$hasRegularRoom) {
+        if ($hasBabyRoom && false === $hasRegularRoom) {
             $this->context->buildViolation($constraint->onlyBabyRoomsMessage)
                 ->addViolation();
         }

tests/Form/Model/ParticipantEditDtoTest.php

@@ -363,6 +363,208 @@ class ParticipantEditDtoTest extends TestCase
         $this->assertCount(0, $violations5);
     }
 
+    // =========================================
+    // Ski Pass Validation Tests (Baby Age Exemption)
+    // =========================================
+
+    public function testSkiPassRequiredForAdultInCreateMode(): void
+    {
+        $bookingDto = $this->createBookingDtoWithParticipants([
+            $this->createAdultParticipantWithoutSkiPass('[email protected]'),
+        ]);
+
+        $wrapper = new ParticipantEditDto(
+            participant: $bookingDto->participants[0],
+            bookingContext: $bookingDto,
+        );
+
+        $violations = $this->validator->validate($wrapper, null, ['strict_required']);
+
+        // Should have ski pass violation
+        $skiPassViolations = array_filter(
+            iterator_to_array($violations),
+            fn ($v) => 'participant.skiPass' === $v->getPropertyPath()
+        );
+
+        $this->assertCount(1, $skiPassViolations, 'Adult should require ski pass in create mode');
+    }
+
+    public function testSkiPassNotRequiredForBabyInCreateMode(): void
+    {
+        $bookingDto = $this->createBookingDtoWithParticipants([
+            $this->createBabyParticipantWithoutSkiPass('[email protected]'),
+        ]);
+
+        $wrapper = new ParticipantEditDto(
+            participant: $bookingDto->participants[0],
+            bookingContext: $bookingDto,
+        );
+
+        $violations = $this->validator->validate($wrapper, null, ['strict_required']);
+
+        // Should NOT have ski pass violation for baby
+        $skiPassViolations = array_filter(
+            iterator_to_array($violations),
+            fn ($v) => 'participant.skiPass' === $v->getPropertyPath()
+        );
+
+        $this->assertCount(0, $skiPassViolations, 'Baby (0-2 years) should not require ski pass');
+    }
+
+    public function testSkiPassNotRequiredForTwoYearOldInCreateMode(): void
+    {
+        $travel = new Travel();
+        $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
+        $travel->dateTo = new \DateTimeImmutable('2025-06-08');
+
+        $bookingDto = new BookingDto($travel, 1);
+
+        // Create a participant exactly at BABY_MAX_AGE (2 years old at travel date)
+        $participant = $this->createParticipantWithoutSkiPass('[email protected]');
+        $participant->dateOfBirth = $travel->dateFrom->modify('-2 years');
+        $participant->index = 0;
+        $participant->mobile = '+49 123 456789';
+        $participant->address = new \App\BusProNet\Model\Address();
+        $participant->address->street = 'Test Street 1';
+        $participant->address->postCode = '12345';
+        $participant->address->city = 'Test City';
+        $participant->address->country = 'DE';
+
+        $bookingDto->participants = [$participant];
+
+        $wrapper = new ParticipantEditDto(
+            participant: $bookingDto->participants[0],
+            bookingContext: $bookingDto,
+        );
+
+        $violations = $this->validator->validate($wrapper, null, ['strict_required']);
+
+        // Should NOT have ski pass violation for 2-year-old
+        $skiPassViolations = array_filter(
+            iterator_to_array($violations),
+            fn ($v) => 'participant.skiPass' === $v->getPropertyPath()
+        );
+
+        $this->assertCount(0, $skiPassViolations, 'Participant at BABY_MAX_AGE (2 years) should not require ski pass');
+    }
+
+    public function testSkiPassRequiredForThreeYearOldInCreateMode(): void
+    {
+        $travel = new Travel();
+        $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
+        $travel->dateTo = new \DateTimeImmutable('2025-06-08');
+
+        $bookingDto = new BookingDto($travel, 1);
+
+        // Create a participant just over BABY_MAX_AGE (3 years old at travel date)
+        $participant = $this->createParticipantWithoutSkiPass('[email protected]');
+        $participant->dateOfBirth = $travel->dateFrom->modify('-3 years');
+        $participant->index = 0;
+        $participant->mobile = '+49 123 456789';
+        $participant->address = new \App\BusProNet\Model\Address();
+        $participant->address->street = 'Test Street 1';
+        $participant->address->postCode = '12345';
+        $participant->address->city = 'Test City';
+        $participant->address->country = 'DE';
+
+        $bookingDto->participants = [$participant];
+
+        $wrapper = new ParticipantEditDto(
+            participant: $bookingDto->participants[0],
+            bookingContext: $bookingDto,
+        );
+
+        $violations = $this->validator->validate($wrapper, null, ['strict_required']);
+
+        // Should have ski pass violation for 3-year-old
+        $skiPassViolations = array_filter(
+            iterator_to_array($violations),
+            fn ($v) => 'participant.skiPass' === $v->getPropertyPath()
+        );
+
+        $this->assertCount(1, $skiPassViolations, 'Participant over BABY_MAX_AGE (3 years) should require ski pass');
+    }
+
+    public function testSkiPassValidationSkippedInEditMode(): void
+    {
+        $travel = new Travel();
+        $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
+        $travel->dateTo = new \DateTimeImmutable('2025-06-08');
+
+        $bookingDto = new BookingDto($travel, 1);
+
+        // Create mock booking to simulate edit mode
+        $mockBooking = new \App\BusProNet\Model\Booking();
+        $bookingDto->booking = $mockBooking;
+
+        // Create adult participant without ski pass in edit mode
+        $participant = $this->createParticipantWithoutSkiPass('[email protected]');
+        $participant->dateOfBirth = new \DateTimeImmutable('1990-01-01');
+        $participant->index = 0;
+        $participant->mutable = false;
+        $participant->mobile = '+49 123 456789';
+        $participant->address = new \App\BusProNet\Model\Address();
+        $participant->address->street = 'Test Street 1';
+        $participant->address->postCode = '12345';
+        $participant->address->city = 'Test City';
+        $participant->address->country = 'DE';
+
+        $bookingDto->participants = [$participant];
+
+        $wrapper = new ParticipantEditDto(
+            participant: $bookingDto->participants[0],
+            bookingContext: $bookingDto,
+        );
+
+        $violations = $this->validator->validate($wrapper, null, ['strict_required']);
+
+        // Should NOT have ski pass violation in edit mode
+        $skiPassViolations = array_filter(
+            iterator_to_array($violations),
+            fn ($v) => 'participant.skiPass' === $v->getPropertyPath()
+        );
+
+        $this->assertCount(0, $skiPassViolations, 'Ski pass validation should be skipped in edit mode');
+    }
+
+    public function testSkiPassAgeCalculatedAtTravelDate(): void
+    {
+        $travel = new Travel();
+        $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
+        $travel->dateTo = new \DateTimeImmutable('2025-06-08');
+
+        $bookingDto = new BookingDto($travel, 1);
+
+        // Create a participant who will be 2 at travel date
+        // Born 2023-06-02, travel date 2025-06-01 = 1 year 364 days = 1 year old
+        $participant = $this->createParticipantWithoutSkiPass('[email protected]');
+        $participant->dateOfBirth = new \DateTimeImmutable('2023-06-02');
+        $participant->index = 0;
+        $participant->mobile = '+49 123 456789';
+        $participant->address = new \App\BusProNet\Model\Address();
+        $participant->address->street = 'Test Street 1';
+        $participant->address->postCode = '12345';
+        $participant->address->city = 'Test City';
+        $participant->address->country = 'DE';
+
+        $bookingDto->participants = [$participant];
+
+        $wrapper = new ParticipantEditDto(
+            participant: $bookingDto->participants[0],
+            bookingContext: $bookingDto,
+        );
+
+        $violations = $this->validator->validate($wrapper, null, ['strict_required']);
+
+        // Should NOT have ski pass violation (age calculated at travel date)
+        $skiPassViolations = array_filter(
+            iterator_to_array($violations),
+            fn ($v) => 'participant.skiPass' === $v->getPropertyPath()
+        );
+
+        $this->assertCount(0, $skiPassViolations, 'Age should be calculated at travel date for baby exemption');
+    }
+
     private function createBookingDtoWithParticipants(array $participants): BookingDto
     {
         $travel = new Travel();
@@ -465,4 +667,56 @@ class ParticipantEditDtoTest extends TestCase
 
         return $insurance;
     }
+
+    private function createAdultParticipantWithoutSkiPass(string $email): ParticipantDto
+    {
+        $participant = $this->createValidParticipant(
+            new \DateTimeImmutable('1990-01-01'), // Adult (over 18)
+            $email
+        );
+
+        // Add required fields EXCEPT ski pass
+        $participant->assignedRoomId = 1;
+        $participant->skiPass = null; // No ski pass
+        $participant->transportationOutbound = $this->createMockService();
+        $participant->transportationInbound = $this->createMockService();
+        $participant->insurance = $this->createMockInsurance();
+
+        return $participant;
+    }
+
+    private function createBabyParticipantWithoutSkiPass(string $email): ParticipantDto
+    {
+        // Baby is 1 year old at travel date (2025-06-01)
+        $participant = $this->createValidParticipant(
+            new \DateTimeImmutable('2024-06-01'), // 1 year old at travel date
+            $email
+        );
+
+        // Add required fields EXCEPT ski pass (babies don't need ski pass)
+        $participant->assignedRoomId = 1;
+        $participant->skiPass = null; // No ski pass
+        $participant->transportationOutbound = $this->createMockService();
+        $participant->transportationInbound = $this->createMockService();
+        $participant->insurance = $this->createMockInsurance();
+
+        return $participant;
+    }
+
+    private function createParticipantWithoutSkiPass(string $email): ParticipantDto
+    {
+        $participant = new ParticipantDto();
+        $participant->firstName = 'John';
+        $participant->lastName = 'Doe';
+        $participant->email = $email;
+
+        // Add required fields EXCEPT ski pass
+        $participant->assignedRoomId = 1;
+        $participant->skiPass = null; // No ski pass
+        $participant->transportationOutbound = $this->createMockService();
+        $participant->transportationInbound = $this->createMockService();
+        $participant->insurance = $this->createMockInsurance();
+
+        return $participant;
+    }
 }

tests/Service/ParticipantEligibilityServiceTest.php

@@ -0,0 +1,172 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Service;
+
+use App\BusProNet\Constants;
+use App\BusProNet\Model\Service;
+use App\BusProNet\Model\Travel;
+use App\Form\Model\BookingDto;
+use App\Form\Model\ParticipantDto;
+use App\Service\ParticipantEligibilityService;
+use PHPUnit\Framework\TestCase;
+
+class ParticipantEligibilityServiceTest extends TestCase
+{
+    private ParticipantEligibilityService $service;
+
+    protected function setUp(): void
+    {
+        $this->service = new ParticipantEligibilityService();
+    }
+
+    public function testBabyParticipantIsAlwaysEligible(): void
+    {
+        $travel = $this->createTravelWithNoSkiPasses();
+        $bookingDto = new BookingDto($travel, 1);
+
+        // Create a baby participant (1 year old at travel date)
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = $travel->dateFrom->modify('-1 year');
+        $bookingDto->participants[0] = $participant;
+
+        $result = $this->service->isParticipantEligible($bookingDto, 0);
+
+        $this->assertTrue($result, 'Baby participant (1 year old) should be eligible regardless of ski pass availability');
+    }
+
+    public function testTwoYearOldParticipantIsEligibleAsBaby(): void
+    {
+        $travel = $this->createTravelWithNoSkiPasses();
+        $bookingDto = new BookingDto($travel, 1);
+
+        // Create a participant exactly at BABY_MAX_AGE (2 years old at travel date)
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = $travel->dateFrom->modify('-2 years');
+        $bookingDto->participants[0] = $participant;
+
+        $result = $this->service->isParticipantEligible($bookingDto, 0);
+
+        $this->assertTrue($result, 'Participant at BABY_MAX_AGE (2 years) should be eligible');
+    }
+
+    public function testThreeYearOldParticipantIsNotBabyEligible(): void
+    {
+        $travel = $this->createTravelWithNoSkiPasses();
+        $bookingDto = new BookingDto($travel, 1);
+
+        // Create a participant just over BABY_MAX_AGE (3 years old at travel date)
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = $travel->dateFrom->modify('-3 years');
+        $bookingDto->participants[0] = $participant;
+
+        $result = $this->service->isParticipantEligible($bookingDto, 0);
+
+        $this->assertFalse($result, 'Participant over BABY_MAX_AGE (3 years) should not be eligible without ski passes');
+    }
+
+    public function testAdultParticipantWithSkiPassIsEligible(): void
+    {
+        $travel = $this->createTravelWithSkiPasses();
+        $bookingDto = new BookingDto($travel, 1);
+
+        // Create an adult participant (25 years old at travel date)
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = $travel->dateFrom->modify('-25 years');
+        $bookingDto->participants[0] = $participant;
+
+        $result = $this->service->isParticipantEligible($bookingDto, 0);
+
+        $this->assertTrue($result, 'Adult participant with available ski passes should be eligible');
+    }
+
+    public function testParticipantWithoutDateOfBirthIsNotEligible(): void
+    {
+        $travel = $this->createTravelWithSkiPasses();
+        $bookingDto = new BookingDto($travel, 1);
+
+        // Create a participant without date of birth
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = null;
+        $bookingDto->participants[0] = $participant;
+
+        $result = $this->service->isParticipantEligible($bookingDto, 0);
+
+        $this->assertFalse($result, 'Participant without date of birth should not be eligible');
+    }
+
+    public function testNewbornBabyIsEligible(): void
+    {
+        $travel = $this->createTravelWithNoSkiPasses();
+        $bookingDto = new BookingDto($travel, 1);
+
+        // Create a newborn (born on travel date)
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = $travel->dateFrom;
+        $bookingDto->participants[0] = $participant;
+
+        $result = $this->service->isParticipantEligible($bookingDto, 0);
+
+        $this->assertTrue($result, 'Newborn baby (0 years old) should be eligible');
+    }
+
+    public function testBabyAgeIsCalculatedAtTravelDate(): void
+    {
+        $travel = new Travel();
+        $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
+        $travel->dateTo = new \DateTimeImmutable('2025-06-08');
+        $travel->additionalServices = [];
+
+        $bookingDto = new BookingDto($travel, 1);
+
+        // Create a participant who will be 2 at travel date but 3 now
+        // Born 2023-06-02, travel date 2025-06-01 = 1 year 364 days = 1 year old
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = new \DateTimeImmutable('2023-06-02');
+        $bookingDto->participants[0] = $participant;
+
+        $result = $this->service->isParticipantEligible($bookingDto, 0);
+
+        $this->assertTrue($result, 'Age should be calculated at travel date, not current date');
+    }
+
+    private function createTravelWithNoSkiPasses(): Travel
+    {
+        $travel = new Travel();
+        $travel->dateFrom = new \DateTimeImmutable('+30 days');
+        $travel->dateTo = new \DateTimeImmutable('+37 days');
+        $travel->additionalServices = [];
+
+        return $travel;
+    }
+
+    private function createTravelWithSkiPasses(): Travel
+    {
+        $travel = new Travel();
+        $travel->dateFrom = new \DateTimeImmutable('+30 days');
+        $travel->dateTo = new \DateTimeImmutable('+37 days');
+
+        // Create a ski pass service available for all ages
+        $skiPass = new Service();
+        $skiPass->id = 1;
+        $skiPass->label = 'Test Ski Pass';
+        $skiPass->subType = Constants::TOKEN_SKI_PASS;
+        $skiPass->available = 10;
+        $skiPass->price = 100.0;
+        $skiPass->ageConstraintType = null; // No age constraint
+        $skiPass->dateFrom = $travel->dateFrom;
+        $skiPass->dateTo = $travel->dateTo;
+
+        $travel->additionalServices = [1 => $skiPass];
+
+        return $travel;
+    }
+}