TRYFAIL(debuged_remove(head,"123")); TRYFAIL(traverse(head));
TRYEXPECT(debuged_remove(head,"12346"),mismatch_error); TRYFAIL(traverse(head));
TRYFAIL(debuged_remove(head,"123")); TRYFAIL(traverse(head));
TRYEXPECT(debuged_remove(head,"12346"),mismatch_error); TRYFAIL(traverse(head));