Merge pull request #8 from xi-project/luhn-validator

Luhn validator

library/Xi/Algorithm/Luhn.php

@@ -33,4 +33,17 @@ public function generate($number)
 
         return (int) (implode('', array_reverse($digits)) . abs($stack));
     }
+
+    /**
+     * Validates the given number.
+     *
+     * @param  integer $number
+     * @return boolean
+     */
+    public function validate($number)
+    {
+        $original = substr($number, 0, strlen($number) - 1);
+
+        return $this->generate($original) === $number;
+    }
 }

tests/Xi/Tests/Algorithm/LuhnTest.php

@@ -36,4 +36,59 @@ public function luhnProvider()
             array(456, 4564),
         );
     }
+
+    /**
+     * @test
+     * @dataProvider luhnValidProvider
+     *
+     * @param integer $number
+     * @param integer $expected
+     */
+    public function validatesLuhnChecksum($number)
+    {
+        $luhn = new Luhn();
+
+        $this->assertTrue($luhn->validate($number));
+    }
+
+
+    /**
+     * @return array
+     */
+    public function luhnValidProvider()
+    {
+        return array(
+            array(799273982),
+            array(1230),
+            array(4564),
+        );
+    }
+
+    /**
+     * @test
+     * @dataProvider luhnInvalidProvider
+     *
+     * @param integer $number
+     * @param integer $expected
+     */
+    public function validatesInvalidLuhnChecksum($number)
+    {
+        $luhn = new Luhn();
+
+        $this->assertFalse($luhn->validate($number));
+    }
+
+
+    /**
+     * @return array
+     */
+    public function luhnInvalidProvider()
+    {
+        return array(
+            array(799273983),
+            array(1231),
+            array(4565),
+            array(1),
+        );
+    }
 }