Re: Unit Test of method calling system() - how?

@Caleb

> I would extract a helper from both methods which does the bulk of the
> work (the first 2 lines) but does not exit. Then test the helper and
> don't bother testing the methods that call it.

Hm, I thought all this unit testing was about testing the interface - 
these are private methods. But perhaps this is one of those rare cases 
where you have to do all sorts of tricks? I was wondering if a special 
class for printing usage would be in order?

> You then have the problem that this print_wiki command is printing
> something to stdout, which you want to test. Either capture stdout in
> the test and verify it contains what you want, or use backticks
> (`...`) instead of system in your helper method.

Actually, 'print_wiki' outputs to stderr - which makes sense if you are 
executing a command and piping the output to a file. You want to see the 
usage info as an indicator that your did something wrong (if you did 
mess up), and not have the usage information in the output file!

> Since print_wiki might change its behavior, you might think about
> making the assertion that tests print_wiki's output string somewhat
> loose.... just verify that some expected substring occurs in there
> somewhere, rather than verifying that it is exactly equal to some
> expected string.

Yup, that makes sense.

> $0 is also going to present you some problems in a test... it will not
> be the same value in the test as it is when run from your main
> program. Not sure what to suggest about that without more context.

Better to supply the base name of the script as an argument?

> 3 other points:
> 
>   looks like both methods have an unintended extra trailing + on their
> first line

No??? On my screen they end with + ".wiki".


>   standard style is to use 2 spaces for indentation; you appear to be 
> using 8

I do use a tab space of 2, however, this is the result of pasting from 
vi and then tabs are expanded wildly (I have no solution for this).

>   since the 2 methods are nearly identical, you should pull out the 
> common code.

Sure.



Cheers,


Martin
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