From: "Shot (Piotr Szotkowski)" <shot@...>
Date: 2009-10-15T07:08:16+09:00
Subject: Re: Testing command-line apps with Cucumber: advice?

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James Coglan:

> I'd like to write some Cucumber features
> for a command-line app I'm working on [=E2=80=A6]

> Do I mock Kernel#puts, should I give the app an IO object to
> write output to so I can collect it, or soemthing else entirely?

When I was faced with the same problem (albeit with RSpec rather than
Cucumber, but I doubt it matters here) I ended up with a very thin
wrapper (which I don=E2=80=99t test) that simply calls Executable.new.run a=
nd
then test the Executable with hand-crafted params and StringIOs:

http://github.com/Chastell/art-decomp/blob/master/bin/art-decomp
http://github.com/Chastell/art-decomp/blob/master/lib/art-decomp/executable=
=2Erb
http://github.com/Chastell/art-decomp/blob/master/spec/art-decomp/executabl=
e_spec.rb

As you can see, Executable#initialize=E2=80=99s param defaults to ARGV and
the spec redirects $stderr to a StringIO object to inspect it for the
desired errors.

The same with my other command line
app, this time with input and output:

http://github.com/Chastell/signore/blob/master/bin/signore
http://github.com/Chastell/signore/blob/master/lib/signore/executable.rb
http://github.com/Chastell/signore/blob/master/spec/signore/executable_spec=
=2Erb

Executable#run=E2=80=99s params default to $stdout and $stdin, but the spec=
 uses
StringIOs in their place to be able to =E2=80=98read from=E2=80=99 and =E2=
=80=98write to=E2=80=99 the
Executable.

=E2=80=94 Shot
--=20
=E2=80=98I finally made a difference at work.=E2=80=99
=E2=80=98How many victims?=E2=80=99          [Dilbert]

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