change price data type from float to string

- floats don't suite for prices - use Money so we don't reinvent wheel - don't use Money directly because it doesn't fit use-cases prefectly, so we still use custom proxy value object Price
simara-svatopluk · Jan 23, 2019 · 3f9dc5d · 3f9dc5d
1 parent f48fb4a
commit 3f9dc5d
Show file tree

Hide file tree

Showing 8 changed files with 124 additions and 68 deletions.
diff --git a/composer.json b/composer.json
@@ -10,7 +10,8 @@
 	],
 	"require": {
 		"php": "^7.1",
-		"doctrine/orm": "^2.5"
+		"doctrine/orm": "^2.5",
+		"moneyphp/money": "~3.2"
 	},
 	"require-dev": {
 		"phpunit/phpunit": "~7.0",

diff --git a/src/Domain/Price.php b/src/Domain/Price.php
@@ -2,17 +2,23 @@
 
 namespace Simara\Cart\Domain;
 
+use Money\Money;
+use Money\Number;
+
 class Price
 {
+    private const EURO_TO_CENTS_CONVERTING_BASE = -2;
+    private const CENTS_TO_EURO_CONVERTING_BASE = 2;
 
     /**
-     * @var float
+     * @var Money
      */
     private $withVat;
 
-    public function __construct(float $withVat)
+    public function __construct(string $withVat)
     {
-        $this->withVat = $withVat;
+        $cents = $this->eurToCents($withVat);
+        $this->withVat = Money::EUR($cents);
     }
 
     /**
@@ -23,23 +29,47 @@ public static function sum(array $prices): self
     {
         return array_reduce($prices, function (self $carry, self $price) {
             return $carry->add($price);
-        }, new self(0.0));
+        }, new self('0'));
     }
 
-    public function getWithVat(): float
+    public function getWithVat(): string
     {
-        return $this->withVat;
+        return $this->centsToEurs($this->withVat->getAmount());
     }
 
     public function add(self $adder): self
     {
-        $withVat = $this->withVat + $adder->withVat;
-        return new self($withVat);
+        $withVat = $this->withVat->add($adder->withVat);
+        return self::fromMoney($withVat);
     }
 
     public function multiply(int $multiplier): self
     {
-        $withVat = $this->withVat * $multiplier;
-        return new self($withVat);
+        $withVat = $this->withVat->multiply($multiplier);
+        return self::fromMoney($withVat);
+    }
+
+    private static function fromMoney(Money $withVat): self
+    {
+        $price = new self('0');
+        $price->withVat = $withVat;
+        return $price;
+    }
+
+    private function eurToCents(string $euros): string
+    {
+        $number = Number::fromString($euros);
+        return $number->base10(self::EURO_TO_CENTS_CONVERTING_BASE)->getIntegerPart();
+    }
+
+    private function centsToEurs(string $cents): string
+    {
+        $number = new Number($cents);
+        $inEuro = $number->base10(self::CENTS_TO_EURO_CONVERTING_BASE);
+        if ($inEuro->isInteger()) {
+            return $inEuro->getIntegerPart();
+        } else {
+            return $inEuro->getIntegerPart() . '.' . $inEuro->getFractionalPart();
+        }
     }
 }
diff --git a/src/Infrastructure/DoctrineMapping/PriceType.php b/src/Infrastructure/DoctrineMapping/PriceType.php
@@ -6,6 +6,7 @@
 
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\DBAL\Types\Type;
+use Exception;
 use Simara\Cart\Domain\Price;
 
 class PriceType extends Type
@@ -14,18 +15,21 @@ class PriceType extends Type
 
     public function getSQLDeclaration(array $fieldDeclaration, AbstractPlatform $platform)
     {
-        return 'FLOAT';
+        return 'DECIMAL(8,2)';
     }
     public function convertToPHPValue($value, AbstractPlatform $platform)
     {
-        return new Price((float) $value);
+        if ($value === null) {
+            return null;
+        }
+        return new Price($value);
     }
     public function convertToDatabaseValue($value, AbstractPlatform $platform)
     {
-        if ($value instanceof Price) {
-            return (string) $value->getWithVat();
+        if (!$value instanceof Price) {
+            throw new Exception('Value must be type of Price');
         }
-        return $value;
+        return $value->getWithVat();
     }
     public function getName()
     {

diff --git a/tests/Domain/CartTest.php b/tests/Domain/CartTest.php
@@ -12,45 +12,45 @@ public function testCalculateEmptyCart()
     {
         $cart = new Cart('1');
 
-        $expected = new CartDetail([], new Price(0.0));
+        $expected = new CartDetail([], new Price("0.0"));
 
         Assert::assertEquals($expected, $cart->calculate());
     }
 
     public function testAddSingleProductToEmpty()
     {
         $cart = new Cart('1');
-        $cart->add('a', new Price(10.0));
+        $cart->add('a', new Price("10.0"));
 
-        $expectedItem = new ItemDetail('a', new Price(10.0), 1);
-        $expected = new CartDetail([$expectedItem], new Price(10.0));
+        $expectedItem = new ItemDetail('a', new Price("10.0"), 1);
+        $expected = new CartDetail([$expectedItem], new Price("10.0"));
 
         Assert::assertEquals($expected, $cart->calculate());
     }
 
     public function testAddTwoDifferentProducts()
     {
         $cart = new Cart('1');
-        $cart->add('a', new Price(10.0));
-        $cart->add('b', new Price(20.0), 2);
+        $cart->add('a', new Price("10.0"));
+        $cart->add('b', new Price("20.0"), 2);
 
         $expectedItems = [
-            new ItemDetail('a', new Price(10.0), 1),
-            new ItemDetail('b', new Price(20.0), 2),
+            new ItemDetail('a', new Price("10.0"), 1),
+            new ItemDetail('b', new Price("20.0"), 2),
         ];
-        $expected = new CartDetail($expectedItems, new Price(50.0));
+        $expected = new CartDetail($expectedItems, new Price("50.0"));
 
         Assert::assertEquals($expected, $cart->calculate());
     }
 
     public function testAddSameProductIncrementAmountOnly()
     {
         $cart = new Cart('1');
-        $cart->add('a', new Price(10.0));
-        $cart->add('a', new Price(0.0));
+        $cart->add('a', new Price("10.0"));
+        $cart->add('a', new Price("0.0"));
 
-        $expectedItem = new ItemDetail('a', new Price(10.0), 2);
-        $expected = new CartDetail([$expectedItem], new Price(20.0));
+        $expectedItem = new ItemDetail('a', new Price("10.0"), 2);
+        $expected = new CartDetail([$expectedItem], new Price("20.0"));
 
         Assert::assertEquals($expected, $cart->calculate());
     }
@@ -68,22 +68,22 @@ public function testRemoveNotExistingProduct()
         $this->expectException(ProductNotInCartException::class);
 
         $cart = new Cart('1');
-        $cart->add('a', new Price(10.0));
+        $cart->add('a', new Price("10.0"));
         $cart->remove('x');
     }
 
     public function testRemoveProduct()
     {
         $cart = new Cart('1');
-        $cart->add('a', new Price(10.0));
-        $cart->add('b', new Price(20.0), 2);
+        $cart->add('a', new Price("10.0"));
+        $cart->add('b', new Price("20.0"), 2);
 
         $cart->remove('a');
 
         $expectedItems = [
-            new ItemDetail('b', new Price(20.0), 2),
+            new ItemDetail('b', new Price("20.0"), 2),
         ];
-        $expected = new CartDetail($expectedItems, new Price(40.0));
+        $expected = new CartDetail($expectedItems, new Price("40.0"));
 
         Assert::assertEquals($expected, $cart->calculate());
     }
@@ -93,19 +93,19 @@ public function testChangeAmountOfNotExisting()
         $this->expectException(ProductNotInCartException::class);
 
         $cart = new Cart('1');
-        $cart->add('a', new Price(10.0));
+        $cart->add('a', new Price("10.0"));
 
         $cart->changeAmount('x', 5);
     }
 
     public function testChangeAmount()
     {
         $cart = new Cart('1');
-        $cart->add('a', new Price(10.0));
+        $cart->add('a', new Price("10.0"));
         $cart->changeAmount('a', 5);
 
-        $expectedItem = new ItemDetail('a', new Price(10.0), 5);
-        $expected = new CartDetail([$expectedItem], new Price(50.0));
+        $expectedItem = new ItemDetail('a', new Price("10.0"), 5);
+        $expected = new CartDetail([$expectedItem], new Price("50.0"));
 
         Assert::assertEquals($expected, $cart->calculate());
     }

diff --git a/tests/Domain/ItemTest.php b/tests/Domain/ItemTest.php
@@ -10,79 +10,79 @@ class ItemTest extends TestCase
 
     public function testToDetail()
     {
-        $item = new Item('x', new Price(5.0), 2);
+        $item = new Item('x', new Price("5.0"), 2);
 
-        $expected = new ItemDetail('x', new Price(5.0), 2);
+        $expected = new ItemDetail('x', new Price("5.0"), 2);
 
         Assert::assertEquals($expected, $item->toDetail());
     }
 
     public function testAdd()
     {
-        $item = new Item('x', new Price(5.0), 2);
+        $item = new Item('x', new Price("5.0"), 2);
         $item->add(5);
 
-        $expected = new ItemDetail('x', new Price(5.0), 7);
+        $expected = new ItemDetail('x', new Price("5.0"), 7);
 
         Assert::assertEquals($expected, $item->toDetail());
     }
 
     public function testChangeAmount()
     {
-        $item = new Item('x', new Price(5.0), 2);
+        $item = new Item('x', new Price("5.0"), 2);
         $item->changeAmount(1);
 
-        $expected = new ItemDetail('x', new Price(5.0), 1);
+        $expected = new ItemDetail('x', new Price("5.0"), 1);
 
         Assert::assertEquals($expected, $item->toDetail());
     }
 
     public function testInitialAmountCannotBeNegative()
     {
         $this->expectException(AmountMustBePositiveException::class);
-        new Item('x', new Price(5.0), -1);
+        new Item('x', new Price("5.0"), -1);
     }
 
     public function testInitialAmountCannotBeZero()
     {
         $this->expectException(AmountMustBePositiveException::class);
-        new Item('x', new Price(5.0), 0);
+        new Item('x', new Price("5.0"), 0);
     }
 
     public function testAddNegativeThrowsException()
     {
         $this->expectException(AmountMustBePositiveException::class);
-        $item = new Item('x', new Price(5.0), 1);
+        $item = new Item('x', new Price("5.0"), 1);
         $item->add(-1);
     }
 
     public function testAddZeroThrowsException()
     {
         $this->expectException(AmountMustBePositiveException::class);
-        $item = new Item('x', new Price(5.0), 1);
+        $item = new Item('x', new Price("5.0"), 1);
         $item->add(0);
     }
 
     public function testChangeToNegativeThrowsException()
     {
         $this->expectException(AmountMustBePositiveException::class);
-        $item = new Item('x', new Price(5.0), 1);
+        $item = new Item('x', new Price("5.0"), 1);
         $item->changeAmount(-1);
     }
 
     public function testChangeToZeroThrowsException()
     {
         $this->expectException(AmountMustBePositiveException::class);
-        $item = new Item('x', new Price(5.0), 1);
+        $item = new Item('x', new Price("5.0"), 1);
         $item->changeAmount(0);
     }
 
     public function testCalculateTotalPrice()
     {
-        $item = new Item('x', new Price(5.0), 3);
+        $item = new Item('x', new Price("5.0"), 3);
         $price = $item->calculatePrice();
 
-        $expected = new Price(15.0);
+        $expected = new Price("15.0");
         Assert::assertEquals($expected, $price);
     }
 }
diff --git a/tests/Domain/PriceTest.php b/tests/Domain/PriceTest.php
@@ -10,33 +10,54 @@ class PriceTest extends TestCase
 
     public function testAdd()
     {
-        $a = new Price(10.0);
-        $b = new Price(0.5);
+        $a = new Price("10.0");
+        $b = new Price("0.5");
         $result = $a->add($b);
 
-        $expected = new Price(10.5);
+        $expected = new Price("10.5");
         Assert::assertEquals($expected, $result);
     }
 
     public function testMultiply()
     {
-        $a = new Price(10.3);
+        $a = new Price("10.3");
         $result = $a->multiply(2);
 
-        $expected = new Price(20.6);
+        $expected = new Price("20.6");
         Assert::assertEquals($expected, $result);
     }
 
     public function testSum()
     {
         $prices = [
-            new Price(9.0),
-            new Price(0.7),
-            new Price(0.3),
+            new Price("9.0"),
+            new Price("0.7"),
+            new Price("0.3"),
         ];
 
         $sum = Price::sum($prices);
-        $expected = new Price(10.0);
+        $expected = new Price("10.0");
         Assert::assertEquals($expected, $sum);
     }
+
+    /**
+     * @dataProvider getterTestCases
+     */
+    public function testGetter(string $converted, string $expected)
+    {
+        $price = new Price($converted);
+        $this->assertSame($expected, $price->getWithVat());
+    }
+
+    public function getterTestCases(): array
+    {
+        return [
+            ["0.005", "0"],
+            ["0.05" , "0.05"],
+            ["0.5"  , "0.5"],
+            ["0"    , "0"],
+            ["5"    , "5"],
+            ["5.555", "5.55"],
+        ];
+    }
 }