Adding pt_BR CNPJ alphanumeric generator to Company provider

src/Provider/pt_BR/Company.php

@@ -33,4 +33,23 @@ public function cnpj($formatted = true)
 
         return $formatted ? vsprintf('%d%d.%d%d%d.%d%d%d/%d%d%d%d-%d%d', str_split($n)) : $n;
     }
+
+    /**
+     * A random CNPJ alphanumeric.
+     *
+     * @see http://en.wikipedia.org/wiki/CNPJ
+     *
+     * @param bool $formatted If the number should have dots/slashes/dashes or not.
+     *
+     * @return string
+     */
+    public function cnpjAlpha($formatted = true)
+    {
+        $pool = array_merge(range('A', 'Z'), range('0', '9'));
+        $n = implode('', array_map(fn () => $pool[array_rand($pool)], range(0, 7))) . '0001';
+        $n .= check_digit_alpha($n);
+        $n .= check_digit_alpha($n);
+
+        return $formatted ? vsprintf('%s%s.%s%s%s.%s%s%s/%s%s%s%s-%s%s', str_split($n)) : $n;
+    }
 }

src/Provider/pt_BR/check_digit.php

@@ -37,3 +37,29 @@ function check_digit($numbers)
 
     return $verifier;
 }
+
+/**
+ * Like check_digit(), but accepts alphanumeric strings (A–Z map to 10–35).
+ *
+ * @param string $str
+ *
+ * @return int
+ */
+function check_digit_alpha($str)
+{
+    $str = strtoupper((string) $str);
+    $length = strlen($str);
+    $second_algorithm = $length >= 12;
+    $verifier = 0;
+
+    for ($i = 1; $i <= $length; ++$i) {
+        $c = $str[$length - $i];
+        $val = ord($c) - 48;
+        $multiplier = $second_algorithm ? ($i >= 9 ? $i - 7 : $i + 1) : $i + 1;
+        $verifier += $val * $multiplier;
+    }
+
+    $verifier = 11 - ($verifier % 11);
+
+    return $verifier >= 10 ? 0 : $verifier;
+}

test/Provider/pt_BR/CompanyTest.php

@@ -7,6 +7,8 @@
 use Faker\Provider\pt_BR\Company;
 use Faker\Test\TestCase;
 
+use function Faker\Provider\pt_BR\check_digit_alpha;
+
 /**
  * @group legacy
  */
@@ -20,6 +22,23 @@ public function testCnpjFormatIsValid(): void
         self::assertMatchesRegularExpression('/\d{2}\.\d{3}\.\d{3}\/\d{4}-\d{2}/', $cnpj);
     }
 
+    public function testCnpjAlphaFormatIsValid(): void
+    {
+        $cnpj = $this->faker->cnpjAlpha(false);
+        self::assertMatchesRegularExpression('/^[A-Z0-9]{8}\d{4}\d{2}$/', $cnpj);
+
+        $cnpj = $this->faker->cnpjAlpha(true);
+        self::assertMatchesRegularExpression('/^[A-Z0-9]{2}\.[A-Z0-9]{3}\.[A-Z0-9]{3}\/\d{4}-\d{2}$/', $cnpj);
+    }
+
+    public function testCnpjAlphaCheckDigitsAreValid(): void
+    {
+        $cnpj = $this->faker->cnpjAlpha(false);
+
+        self::assertSame((int) $cnpj[12], check_digit_alpha(substr($cnpj, 0, 12)));
+        self::assertSame((int) $cnpj[13], check_digit_alpha(substr($cnpj, 0, 13)));
+    }
+
     protected function getProviders(): iterable
     {
         yield new Company($this->faker);