From 9ef3cf04153150ebe3f5d12dc4b38d982710b28c Mon Sep 17 00:00:00 2001
From: "Emanuele \"ToX\" Toscano" <toss82@gmail.com>
Date: Mon, 31 Jul 2023 15:09:19 +0200
Subject: [PATCH] Added stricter checks for Belgium and Germany

---
 .gitignore        |  3 +-
 composer.json     |  2 +-
 phpunit.xml.dist  | 26 ++++++++--------
 src/VatNumber.php | 77 ++++++++++++++++++++++++++++++++++++-----------
 tests/Test.php    | 32 +++++++++++---------
 5 files changed, 91 insertions(+), 49 deletions(-)

diff --git a/.gitignore b/.gitignore
index e3c2ef3..d558b74 100644
--- a/.gitignore
+++ b/.gitignore
@@ -23,4 +23,5 @@ Thumbs.db
 
 # IDE folders
 /.idea
-/.vscode
\ No newline at end of file
+/.vscode
+.phpunit.result.cache
diff --git a/composer.json b/composer.json
index 4d91581..4e9b02a 100644
--- a/composer.json
+++ b/composer.json
@@ -27,7 +27,7 @@
         "php": ">=7.0.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^5.5"
+        "phpunit/phpunit": "*"
     },
     "autoload": {
         "psr-4": {
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 62fec58..df69949 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,15 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
-
-<phpunit bootstrap="vendor/autoload.php" colors="true">
-    <testsuites>
-        <testsuite name="VatNumber Test Suite">
-            <directory>tests</directory>
-        </testsuite>
-    </testsuites>
-
-    <filter>
-        <whitelist>
-            <directory suffix=".php">src</directory>
-        </whitelist>
-    </filter>
-</phpunit>
\ No newline at end of file
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" bootstrap="vendor/autoload.php" colors="true" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd">
+  <coverage>
+    <include>
+      <directory suffix=".php">src</directory>
+    </include>
+  </coverage>
+  <testsuites>
+    <testsuite name="VatNumber Test Suite">
+      <directory>tests</directory>
+    </testsuite>
+  </testsuites>
+</phpunit>
diff --git a/src/VatNumber.php b/src/VatNumber.php
index 56241a3..f6e5b73 100644
--- a/src/VatNumber.php
+++ b/src/VatNumber.php
@@ -21,7 +21,6 @@ class VatNumber
      *
      * @param string $country Country code
      * @param string $code    VAT number
-     *
      * @return bool
      */
     public static function check(string $country, string $code): bool
@@ -39,7 +38,7 @@ public static function check(string $country, string $code): bool
             return self::_checkLength($code, 11, 11) && self::_numbersOnly($code);
         case "BE":
             // 10 digits.
-            return self::_checkLength($code, 10, 10) && self::_numbersOnly($code);
+            return self::_checkLength($code, 10, 10) && self::_checkBelgium($code);
         case "BG":
             // 9 or 10 digits.
             return self::_checkLength($code, 9, 10) && self::_numbersOnly($code);
@@ -49,6 +48,9 @@ public static function check(string $country, string $code): bool
         case "CA":
             // 9 characters.
             return self::_checkLength($code, 9, 9);
+        case "CO":
+            // 10 characters.
+            return self::_checkLength($code, 10, 10);
         case "HR":
             // 11 digits.
             return self::_checkLength($code, 11, 11) && self::_numbersOnly($code);
@@ -75,7 +77,7 @@ public static function check(string $country, string $code): bool
             return self::_checkLength($code, 11, 11) && self::_checkFrance($code);
         case "DE":
             // 9 or 10 digits.
-            return self::_checkLength($code, 9, 9) && self::_numbersOnly($code);
+            return self::_checkLength($code, 9, 9) && self::_checkGermany($code);
         case "EL":
             // 9 digits.
             return self::_checkLength($code, 9, 9) && self::_numbersOnly($code);
@@ -186,7 +188,6 @@ public static function check(string $country, string $code): bool
      * @param string $code VAT number
      * @param int    $min  Min length
      * @param int    $max  Max length
-     *
      * @return bool
      */
     private static function _checkLength(string $code, int $min, int $max): bool
@@ -198,7 +199,6 @@ private static function _checkLength(string $code, int $min, int $max): bool
      * Checks that a string is only numbers.
      *
      * @param string $code VAT number
-     *
      * @return bool
      */
     private static function _numbersOnly(string $code): bool
@@ -211,7 +211,6 @@ private static function _numbersOnly(string $code): bool
      * Eg. K99999999L or L99999999G
      *
      * @param string $code VAT number
-     *
      * @return bool
      */
     private static function _checkAlbania(string $code): bool
@@ -228,7 +227,6 @@ private static function _checkAlbania(string $code): bool
      * Eg. U12345678
      *
      * @param string $code VAT number
-     *
      * @return bool
      */
     private static function _checkAustria(string $code): bool
@@ -241,12 +239,30 @@ private static function _checkAustria(string $code): bool
         return true;
     }
 
+    /**
+     * Additional validations for Belgium
+     * Eg. 09999999XX
+     *
+     * @param string $code VAT number
+     * @return bool
+     */
+    private static function _checkBelgium(string $code): bool
+    {
+        if (!preg_match('/^\d{8}[0-9][0-9]$/', $code)) {
+            return false;
+        }
+
+        $checkDigits = substr($code, 0, 8) % 97;
+        $checkDigits = sprintf('%02d', 97 - $checkDigits);
+
+        return substr($code, 8, 2) == $checkDigits;
+    }
+
     /**
      * Additional validations for Switzerland
      * Eg. 123.456.789
      *
      * @param string $code VAT number
-     *
      * @return bool
      */
     private static function _checkSwitzerland(string $code): bool
@@ -264,7 +280,6 @@ private static function _checkSwitzerland(string $code): bool
      * Eg. 12345678X
      *
      * @param string $code VAT number
-     *
      * @return bool
      */
     private static function _checkCyprus(string $code): bool
@@ -282,7 +297,6 @@ private static function _checkCyprus(string $code): bool
      * Eg. 12345678901 - X1234567890 - 1X123456789 - XX123456789
      *
      * @param string $code VAT number
-     *
      * @return bool
      */
     private static function _checkFrance(string $code): bool
@@ -300,11 +314,45 @@ private static function _checkFrance(string $code): bool
         return true;
     }
 
+    /**
+    * Additional validations for Germany
+    * Eg. 122265872
+    *
+    * @param string $code VAT number
+    * @return bool
+    */
+    private static function _checkGermany(string $code): bool
+    {
+        $count = 1;
+        $product = 10;
+        $sum = 0;
+        $checkDigit = intval(substr($code, -1));
+        $result = 0;
+
+        while ($count < 9) {
+            $sum = (intval(substr($code, $count - 1, 1)) + $product) % 10;
+
+            if ($sum === 0) {
+                $sum = 10;
+            }
+
+            $product = (2 * $sum) % 11;
+            $count++;
+        }
+
+        $result = 11 - $product;
+
+        if ($result === 10) {
+            $result = 0;
+        }
+
+        return $result === $checkDigit;
+    }
+
     /**
      * Additional validations for Ireland
      *
      * @param string $code Regional VAT code
-     *
      * @return bool
      */
     private static function _checkIreland(string $code): bool
@@ -324,7 +372,6 @@ private static function _checkIreland(string $code): bool
      * Additional validations for Italy
      *
      * @param string $code Regional VAT code
-     *
      * @return bool
      */
     private static function _checkItaly(string $code): bool
@@ -356,7 +403,6 @@ private static function _checkItaly(string $code): bool
      * Eg. MK4032013544513
      *
      * @param string $code Regional VAT code
-     *
      * @return bool
      */
     private static function _checkNorthMacedonia(string $code): bool
@@ -373,7 +419,6 @@ private static function _checkNorthMacedonia(string $code): bool
      * Eg. 01012345-0001
      *
      * @param string $code Regional VAT code
-     *
      * @return bool
      */
     private static function _checkNigeria(string $code): bool
@@ -389,7 +434,6 @@ private static function _checkNigeria(string $code): bool
      * Additional validations for Netherlands
      *
      * @param string $code Regional VAT code
-     *
      * @return bool
      */
     private static function _checkNetherlands(string $code): bool
@@ -406,7 +450,6 @@ private static function _checkNetherlands(string $code): bool
      * Additional validations for Norway
      *
      * @param string $code Regional VAT code
-     *
      * @return bool
      */
     private static function _checkNorway(string $code): bool
@@ -427,7 +470,6 @@ private static function _checkNorway(string $code): bool
      * Additional validations for Russia
      *
      * @param string $code Regional VAT code
-     *
      * @return bool
      */
     private static function _checkRussia(string $code): bool
@@ -443,7 +485,6 @@ private static function _checkRussia(string $code): bool
      * Additional validations for Spain
      *
      * @param string $code Regional VAT code
-     *
      * @return bool
      */
     private static function _checkSpain(string $code): bool
diff --git a/tests/Test.php b/tests/Test.php
index 1b29706..3de1fa2 100644
--- a/tests/Test.php
+++ b/tests/Test.php
@@ -8,13 +8,13 @@
 
 namespace Tox82\Tests\Validator;
 
-use PHPUnit_Framework_TestCase;
+use PHPUnit\Framework\TestCase;
 use Tox82\VatNumber;
 
 /**
  * Tests!
  */
-class VatTest extends PHPUnit_Framework_TestCase
+class VatTest extends TestCase
 {
     /**
      * Valid VAT numbers should be valid!
@@ -27,38 +27,41 @@ public function testCheckValids()
         $this->assertTrue(VatNumber::check('AL', 'L99999999G'));
         $this->assertTrue(VatNumber::check('AT', 'U12345678'));
         $this->assertTrue(VatNumber::check('AU', '12345678901'));
-        $this->assertTrue(VatNumber::check('BE', '1234567890'));
+        $this->assertTrue(VatNumber::check('BE', '1234567894'));
         $this->assertTrue(VatNumber::check('BG', '123456789'));
         $this->assertTrue(VatNumber::check('BG', '1234567890'));
         $this->assertTrue(VatNumber::check('BY', '190190190'));
-        $this->assertTrue(VatNumber::check('HR', '12345678901'));
         $this->assertTrue(VatNumber::check('CA', '1234567AB'));
         $this->assertTrue(VatNumber::check('CH', '123.456.789'));
         $this->assertTrue(VatNumber::check('CY', '12345678X'));
         $this->assertTrue(VatNumber::check('CZ', '12345678'));
         $this->assertTrue(VatNumber::check('CZ', '123456789'));
         $this->assertTrue(VatNumber::check('CZ', '1234567890'));
+        $this->assertTrue(VatNumber::check('DE', '122265872'));
         $this->assertTrue(VatNumber::check('DK', '12345678'));
         $this->assertTrue(VatNumber::check('EE', '123456789'));
+        $this->assertTrue(VatNumber::check('EL', '123456789'));
+        $this->assertTrue(VatNumber::check('ES', '12345678X'));
+        $this->assertTrue(VatNumber::check('ES', 'X12345678'));
+        $this->assertTrue(VatNumber::check('ES', 'X1234567X'));
         $this->assertTrue(VatNumber::check('FI', '12345678'));
         $this->assertTrue(VatNumber::check('FR', '12345678901'));
         $this->assertTrue(VatNumber::check('FR', '12345678901'));
-        $this->assertTrue(VatNumber::check('FR', 'X1234567890'));
         $this->assertTrue(VatNumber::check('FR', '1X123456789'));
+        $this->assertTrue(VatNumber::check('FR', 'X1234567890'));
         $this->assertTrue(VatNumber::check('FR', 'XX123456789'));
-        $this->assertTrue(VatNumber::check('DE', '123456789'));
-        $this->assertTrue(VatNumber::check('EL', '123456789'));
         $this->assertTrue(VatNumber::check('GB', '123456789'));
+        $this->assertTrue(VatNumber::check('HR', '12345678901'));
         $this->assertTrue(VatNumber::check('HU', '12345678'));
         $this->assertTrue(VatNumber::check('IE', '1234567X'));
-        $this->assertTrue(VatNumber::check('IE', '1X23456X'));
         $this->assertTrue(VatNumber::check('IE', '1234567XX'));
+        $this->assertTrue(VatNumber::check('IE', '1X23456X'));
         $this->assertTrue(VatNumber::check('IT', '00154189997'));
-        $this->assertTrue(VatNumber::check('LV', '12345678901'));
         $this->assertTrue(VatNumber::check('IT', '01573850516'));
         $this->assertTrue(VatNumber::check('LT', '123456789'));
         $this->assertTrue(VatNumber::check('LT', '123456789012'));
         $this->assertTrue(VatNumber::check('LU', '12345678'));
+        $this->assertTrue(VatNumber::check('LV', '12345678901'));
         $this->assertTrue(VatNumber::check('MK', 'MK4032013544513'));
         $this->assertTrue(VatNumber::check('MT', '12345678'));
         $this->assertTrue(VatNumber::check('NG', '01012345-0001'));
@@ -79,12 +82,9 @@ public function testCheckValids()
         $this->assertTrue(VatNumber::check('RU', '9999999999'));
         $this->assertTrue(VatNumber::check('RU', '999999999999'));
         $this->assertTrue(VatNumber::check('RU', '9999999999999'));
-        $this->assertTrue(VatNumber::check('SK', '1234567890'));
-        $this->assertTrue(VatNumber::check('SI', '12345678'));
-        $this->assertTrue(VatNumber::check('ES', 'X12345678'));
-        $this->assertTrue(VatNumber::check('ES', '12345678X'));
-        $this->assertTrue(VatNumber::check('ES', 'X1234567X'));
         $this->assertTrue(VatNumber::check('SE', '123456789012'));
+        $this->assertTrue(VatNumber::check('SI', '12345678'));
+        $this->assertTrue(VatNumber::check('SK', '1234567890'));
     }
 
     /**
@@ -108,6 +108,7 @@ public function testCheckWithInvalidLength()
         $this->assertFalse(VatNumber::check('AT', 'U123456780'));
         $this->assertFalse(VatNumber::check('AU', '123456789012'));
         $this->assertFalse(VatNumber::check('CA', '1234567ABC'));
+        $this->assertFalse(VatNumber::check('DE', '12226587'));
         $this->assertFalse(VatNumber::check('IT', '001541899970'));
         $this->assertFalse(VatNumber::check('MK', 'MK40320135445131'));
         $this->assertFalse(VatNumber::check('RU', '99999999999999'));
@@ -124,8 +125,9 @@ public function testCheckWithInvalidCharacters()
         $this->assertFalse(VatNumber::check('AL', 'K999999999'));
         $this->assertFalse(VatNumber::check('AT', 'A12345678'));
         $this->assertFalse(VatNumber::check('AU', 'A2345678901'));
+        $this->assertFalse(VatNumber::check('DE', '122265873'));
         $this->assertFalse(VatNumber::check('IT', '01573850514'));
         $this->assertFalse(VatNumber::check('MK', 'AA4032013544513'));
         $this->assertFalse(VatNumber::check('NO', '123456789MV'));
     }
-}
\ No newline at end of file
+}