Improve barcode formatter speed, add tests for it

readme.md

@@ -328,7 +328,7 @@ The populator uses name and column type guessers to populate each column with re
 ```php
 <?php
 $populator->addEntity('Book', 5, array(
-  'ISBN' => function() use ($generator) { return $generator->randomNumber(13); }
+  'ISBN' => function() use ($generator) { return $generator->ean13(); }
 ));
 ```
 

src/Faker/Provider/Barcode.php

@@ -9,21 +9,22 @@ class Barcode extends \Faker\Provider\Base
 {
     private function ean($length = 13)
     {
-        $code = array();
-        for ($i = 0; $i < $length - 1; $i++) {
-            $code[] = static::randomDigit();
-        }
+        $code = $this->numerify(str_repeat('#', $length - 1));
 
-        $sequence = $length == 8 ? array(3, 1) : array(1, 3);
+        return $code . static::eanChecksum($code);
+    }
 
+    /**
+     * Utility function for computing EAN checksums
+     */
+    protected static function eanChecksum($input)
+    {
+        $sequence = (strlen($input) - 1) == 8 ? array(3, 1) : array(1, 3);
         $sums = 0;
-        foreach ($code as $n => $digit) {
+        foreach (str_split($input) as $n => $digit) {
             $sums += $digit * $sequence[$n % 2];
         }
-
-        $checksum = (10 - $sums % 10) % 10;
-
-        return implode('', $code) . $checksum;
+        return (10 - $sums % 10) % 10;
     }
 
     /**

test/Faker/Provider/BarcodeTest.php

@@ -7,20 +7,39 @@
 
 class BarcodeTest extends \PHPUnit_Framework_TestCase
 {
+    private $faker;
+
     public function setUp()
     {
         $faker = new Generator();
         $faker->addProvider(new Barcode($faker));
+        $faker->seed(0);
         $this->faker = $faker;
     }
 
     public function testEan8()
     {
-        $this->assertRegExp('/[\d]{8}/', $this->faker->ean8());
+        $code = $this->faker->ean8();
+        $this->assertRegExp('/^\d{8}$/i', $code);
+        $codeWitoutChecksum = substr($code, 0, -1);
+        $checksum = substr($code, -1);
+        $this->assertEquals(TestableBarcode::eanChecksum($codeWitoutChecksum), $checksum);
     }
 
     public function testEan13()
     {
-        $this->assertRegExp('/[\d]{13}/', $this->faker->ean13());
+        $code = $this->faker->ean13();
+        $this->assertRegExp('/^\d{13}$/i', $code);
+        $codeWitoutChecksum = substr($code, 0, -1);
+        $checksum = substr($code, -1);
+        $this->assertEquals(TestableBarcode::eanChecksum($codeWitoutChecksum), $checksum);
+    }
+}
+
+class TestableBarcode extends Barcode
+{
+    public static function eanChecksum($input)
+    {
+        return parent::eanChecksum($input);
     }
 }