Implement \Serializable on Number (#26)

* make number json and php serializable

* lint. remove json

* cleanup

Author: Ekman

src/Number.php

@@ -33,7 +33,7 @@
 /**
  * Input for the Luhn Algorithm contains a number and a check digit.
  */
-class Number implements NumberInterface
+class Number implements NumberInterface, \Serializable
 {
     /**
      * @var string
@@ -114,4 +114,14 @@ public function __toString()
     {
         return $this->number . $this->checkDigit;
     }
+
+    public function serialize()
+    {
+        return serialize([$this->number, $this->checkDigit]);
+    }
+
+    public function unserialize($serialized)
+    {
+        list($this->number, $this->checkDigit) = unserialize($serialized);
+    }
 }

tests/NumberTest.php

@@ -121,4 +121,14 @@ public function provideProperties()
             "Valid number and check digit (null)" => [123, null],
         ];
     }
+
+    public function testSerialize()
+    {
+        $number = new Number(133, 7);
+        $serialized = serialize($number);
+        $other = unserialize($serialized);
+        $this->assertInstanceOf(Number::class, $other);
+        $this->assertEquals(133, $other->getNumber());
+        $this->assertEquals(7, $other->getCheckDigit());
+    }
 }