[Ruby] Forcing exceptions in tests

[Laurel Fan]

On 10/31/07, Tom Lianza <tom at lianza.org> wrote:
> I wanted to write some tests such that I can force that exception to happen,
> primarily to ensure that other models which make use of ProductImage will
> gracefully handle errors if they happen from within it.

Sounds like a job for mocks!

Mocha[1] and Flexmock[2] are the two mocking frameworks that I know
of.  Their feature sets are pretty similar.  They are both much nicer
than the naive way of making "mock" objects (subclassing and
overriding) which it sounds like you have come across and do not like.

Check out the mocha/flexmock documentation and examples for details,
but essentially you do something like:

flexmock(HTTP).should_receive(:get).and_raise(TimeoutError)

and all calls to HTTP::get now return TimeoutError.

[1]: http://mocha.rubyforge.org/
[2]: http://onestepback.org/software/flexmock/

-- 
Laurel Fan
http://blog.gorgorg.org