Update tests to use more strict data types instead of mixed.

tests/arab_to_roman.aer

@@ -3,13 +3,13 @@ class Program {
 	private function num2Roman(int $num) {
 		int $n = intval($num);
 		string $result = '';
-		mixed $lookup = array('M' => 1000, 'CM' => 900, 'D' => 500, 'CD' => 400,
+		int[] $lookup = array('M' => 1000, 'CM' => 900, 'D' => 500, 'CD' => 400,
 			'C' => 100, 'XC' => 90, 'L' => 50, 'XL' => 40,
 			'X' => 10, 'IX' => 9, 'V' => 5, 'IV' => 4, 'I' => 1);
 
 		int $matches;
 		foreach($lookup as $roman => $value) {
-			 $matches = intval($n / $value);
+			$matches = intval($n / $value);
 			$result += str_repeat($roman, $matches);
 			$n = $n % $value;
 		}