I'm more concerned as to why you think you need to. If you wrote the module, you should be able to go through the various execution paths and determine what should be out there. Then, use UNIVERSAL::can to test your theories. If you're right on all counts, then you did it right.

Now, if you cannot (or will not) do an execution trace by hand (or in your head), then that's another problem altogether.

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We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.