+ (assert (raises-error? (do-open t :error :error)))
+
+ (assert (raises-error?
+ (do-open nil nil :error :io)))
+ (assert (not
+ (do-open nil :error nil :io)))
+ (assert (not
+ (do-open t nil :error :io)))
+ (assert (raises-error?
+ (do-open t :error nil :io)))
+ (assert (not
+ (do-open nil nil nil :io)))
+ (assert (raises-error?
+ (do-open nil :error :error :io)))
+ (assert (not
+ (do-open t nil nil :io)))
+ (assert (raises-error? (do-open t :error :error :io)))))