Completing unit test

Author: chdemko

tests/BitArray/BitArrayTest.php

@@ -424,8 +424,10 @@ public function cases_copy()
 			['11010011', 2, 7, 4, '11110011'],
 			['11010011', 2, -4, 4, '11001111'],
 			['11010011', 9, -4, 4, '11010011'],
+			['11010011', 2, -9, 4, '11110111'],
 			['11010011', 0, 3, null, '10011011'],
 			['11010011', 0, 3, -3, '10010011'],
+			['11010011', 0, 3, -9, '11010011'],
 		];
 	}