Lower the minimum PHP version to PHP 7.0. (#11)

* Downgrade to allow for PHP 7.0

* Fix PH P 7.0

* Fix ? operator

* Fix

* Add test for number properties

* Cleanup

* Cleanup

* Cleanup

Author: Ekman

.travis.yml

@@ -1,6 +1,7 @@
 language: php
 
 php:
+  - '7.0'
   - '7.1'
   - '7.2'
 

composer.json

@@ -2,6 +2,9 @@
 	"name": "nekman/luhn-algorithm",
 	"type": "library",
 	"description": "Implementation of the Luhn algorithm in PHP. Used in validation of credit card numbers and some national identification numbers.",
+	"prefer-stable": true,
+	"prefer-lowest": true,
+	"minimum-stability": "stable",
 	"keywords": [
 		"luhn",
 		"credit",
@@ -31,10 +34,10 @@
 		}
 	},
 	"require": {
-		"php": "^7.1"
+		"php": "^7.0"
 	},
 	"require-dev": {
-		"phpunit/phpunit": "^6.5",
-		"friendsofphp/php-cs-fixer": "^2.10"
+		"phpunit/phpunit": "^6.0",
+		"friendsofphp/php-cs-fixer": "^2.0"
 	}
 }

src/Contract/NumberInterface.php

@@ -44,5 +44,5 @@ public function getNumber(): string;
      *
      * @return int|null The check digit or null if it has not been calculated yet.
      */
-    public function getCheckDigit(): ?int;
+    public function getCheckDigit();
 }

src/Number.php

@@ -35,7 +35,7 @@
 class Number implements NumberInterface
 {
     /**
-     * @var int
+     * @var string
      */
     private $number;
 
@@ -49,7 +49,7 @@ class Number implements NumberInterface
      * @param string $number The number.
      * @param int|null $checkDigit [Optional] The check digit for the number.
      */
-    public function __construct(string $number, ?int $checkDigit = null)
+    public function __construct(string $number, int $checkDigit = null)
     {
         if (!is_numeric($number)) {
             throw new \InvalidArgumentException("Expects \$number to be a number, \"{$number}\" given.");
@@ -95,7 +95,7 @@ public function getNumber(): string
     /**
      * {@inheritdoc}
      */
-    public function getCheckDigit(): ?int
+    public function getCheckDigit()
     {
         return $this->checkDigit;
     }

tests/NumberTest.php

@@ -98,4 +98,22 @@ public function provideNew_fail()
             ['123 ', null, \InvalidArgumentException::class],
         ];
     }
+
+    /**
+     * @dataProvider provideProperties
+     */
+    public function testProperties($input, $checkDigit)
+    {
+        $number = new Number($input, $checkDigit);
+        $this->assertEquals($input, $number->getNumber());
+        $this->assertEquals($checkDigit, $number->getCheckDigit());
+    }
+
+    public function provideProperties()
+    {
+        return [
+            [123, 1],
+            [123, null],
+        ];
+    }
 }