ldc-boutique-cnc-sable/tests/Unit/Domain/Models/ValueObjects/DiscountValueTest.php

<?php

declare(strict_types=1);

namespace Tests\Unit\Domain\Models\ValueObjects;

use Domain\Enums\DiscountType;
use Domain\Models\ValueObjects\DiscountValue;
use Money\Currency;
use Money\Money;

describe('DiscountValue', function () {

    function getDiscountMoney(int $amount, string $currency = 'EUR'): Money
    {
        return new Money($amount, new Currency($currency));
    }

    it('can instantiate from amount', function () {
        // GIVEN
        $amount = getDiscountMoney(100);

        // WHEN
        $vo = DiscountValue::fromAmount($amount);

        // THEN
        expect($vo)->toBeInstanceOf(DiscountValue::class);
        expect($vo->isPercentage())->toBeFalse();
    });

    it('can instantiate from percentage', function () {
        // GIVEN
        $rate = 20;

        // WHEN
        $vo = DiscountValue::fromPercentage($rate);

        // THEN
        expect($vo)->toBeInstanceOf(DiscountValue::class);
        expect($vo->isPercentage())->toBeTrue();
    });

    it('throws exception if percentage is negative', function () {
        // GIVEN
        // WHEN
        $action = fn () => DiscountValue::fromPercentage(-1);

        // THEN
        expect($action)->toThrow(\DomainException::class);
    });

    it('throws exception if percentage is greater than 100', function () {
        // GIVEN
        $rate = 101;

        // WHEN
        $action = fn () => DiscountValue::fromPercentage($rate);

        // THEN
        expect($action)->toThrow(\DomainException::class);
    });

    it('throws exception if amount is negative', function () {
        // GIVEN
        $amount = getDiscountMoney(-1);

        // WHEN
        $action = fn () => DiscountValue::fromAmount($amount);

        // THEN
        expect($action)->toThrow(\DomainException::class);
    });

    it('returns the correct value for amount discount', function () {
        // GIVEN
        $amount = getDiscountMoney(50);

        // WHEN
        $vo     = DiscountValue::fromAmount($amount);

        // THEN
        expect($vo->value())->toEqual($amount);
    });

    it('returns the correct value for percentage discount', function () {
        // GIVEN
        $rate = 20;

        // WHEN
        $vo   = DiscountValue::fromPercentage($rate);

        // THEN
        expect($vo->value())->toBe($rate);
    });

    it('returns the correct percentage rate', function () {
        // GIVEN
        $percentage = 20;

        // WHEN
        $vo = DiscountValue::fromPercentage($percentage);

        // THEN
        expect($vo->getPercentageRate())->toBe(0.2);
    });

    it('throws exception when getting percentage rate from amount discount', function () {
        // GIVEN
        $amount = getDiscountMoney(100);
        $vo     = DiscountValue::fromAmount($amount);

        // WHEN
        $action = fn () => $vo->getPercentageRate();

        // THEN
        expect($action)->toThrow(\DomainException::class);
    });

    it('returns the correct amount', function () {
        // GIVEN
        $amount = getDiscountMoney(100);

        // WHEN
        $vo = DiscountValue::fromAmount($amount);

        // THEN
        expect($vo->getAmount())->toEqual($amount);
    });

    it('throws exception when getting amount from percentage discount', function () {
        // GIVEN
        $vo = DiscountValue::fromPercentage(10);

        // WHEN
        $action = fn () => $vo->getAmount();

        // THEN
        expect($action)->toThrow(\DomainException::class);
    });

    it('calculates discount amount correctly for percentage', function () {
        // GIVEN
        $basePrice = getDiscountMoney(1000);
        $vo        = DiscountValue::fromPercentage(20); // 20%

        // WHEN
        $result = $vo->calculateDiscountAmount($basePrice);

        // THEN
        expect($result->getAmount())->toBe('200');
    });

    it('calculates discount amount correctly for fixed amount', function () {
        // GIVEN
        $basePrice = getDiscountMoney(1000);
        $vo        = DiscountValue::fromAmount(getDiscountMoney(50));

        // WHEN
        $result = $vo->calculateDiscountAmount($basePrice);

        // THEN
        expect($result->getAmount())->toBe('50');
    });

    it('throws exception on currency mismatch when calculating discount', function () {
        // GIVEN
        $basePrice = getDiscountMoney(1000, 'EUR');
        $vo        = DiscountValue::fromAmount(getDiscountMoney(50, 'USD'));

        // WHEN
        $action = fn () => $vo->calculateDiscountAmount($basePrice);

        // THEN
        expect($action)->toThrow(\DomainException::class);
    });
});

describe('DiscountValue exceptions', function (): void {
    it('throws when percentage is missing for percent type', function (): void {
        // GIVEN
        $reflection = new \ReflectionClass(DiscountValue::class);
        $method     = $reflection->getMethod('__construct');
        $vo         = $reflection->newInstanceWithoutConstructor();
        // WHEN
        $action = fn () => $method->invoke($vo, DiscountType::PERCENT, null, null);
        // THEN
        expect($action)->toThrow(\DomainException::class);
    });

    it('throws when amount is missing for amount type', function (): void {
        // GIVEN
        $reflection = new \ReflectionClass(DiscountValue::class);
        $method     = $reflection->getMethod('__construct');
        $vo         = $reflection->newInstanceWithoutConstructor();
        // WHEN
        $action = fn () => $method->invoke($vo, DiscountType::AMOUNT, null, null);
        // THEN
        expect($action)->toThrow(\DomainException::class);
    });

    it('throws unexpected value if percentage is null', function (): void {
        // GIVEN
        $reflection = new \ReflectionClass(DiscountValue::class);
        $vo         = $reflection->newInstanceWithoutConstructor();
        $prop       = $reflection->getProperty('type');
        $prop->setValue($vo, DiscountType::PERCENT);
        $prop2 = $reflection->getProperty('percentage');
        $prop2->setValue($vo, null);

        // WHEN
        $action = fn () => $vo->getPercentage();
        // THEN
        expect($action)->toThrow(\DomainException::class);
    });

    it('throws unexpected value if amount is null', function (): void {
        // GIVEN
        $reflection = new \ReflectionClass(DiscountValue::class);
        $vo         = $reflection->newInstanceWithoutConstructor();
        $prop       = $reflection->getProperty('type');
        $prop->setValue($vo, DiscountType::AMOUNT);
        $prop2 = $reflection->getProperty('amount');
        $prop2->setValue($vo, null);

        // WHEN
        $action = fn () => $vo->getAmount();
        // THEN
        expect($action)->toThrow(\DomainException::class);
    });
});