[rspec-devel] [Proposed Refactoring] - Current ExampleSpace class subclasses Test::Unit::TestCase

[David Chelimsky]

On 8/22/07, Scott Taylor <mailing_lists at railsnewbie.com> wrote:
>
> On Aug 22, 2007, at 3:02 PM, aslak hellesoy wrote:
>
> > On 8/22/07, Dan North <dan at tastapod.com> wrote:
> >> Hi Aslak.
> >>
> >> aslak hellesoy wrote:
> >>> On 8/21/07, Brian Takita <brian.takita at gmail.com> wrote:
> >>>
> >>>> This is a way to utilize Test::Unit in rspec.
> >>>>
> >>>> There are a number of BDD frameworks that utilize Test::Unit to
> >>>> create
> >>>> a simple implementation.
> >>>>
> >>>> This could also be a first step to using Test::Unit's runner.
> >>>>
> >> A similar conversation happened in the early days of jbehave about
> >> whether to use junit's runner. We decided to go with our own runner
> >> (like rspec did) because we wanted it to do other stuff (mostly
> >> lifecycle callbacks).
> >>> Using Test::Unit's runner might be compelling, but I don't know how
> >>> easy it will be to make it behave like today's RSpec. We have a
> >>> lot of
> >>> extra command line options, different output and so on. I'm not sure
> >>> what it takes to make it happen.
> >>>
> >> I don't think it would be too difficult to write an adapter to run
> >> under
> >> test::unit. Right now, the describe method captures a block of code -
> >> the description (aka context) - and the it method captures another
> >> block
> >> of code - the example. You can replace these methods as follows:
> >>
> >> - describe Sheep dynamically creates a class called SheepTest that
> >> extends a subclass of TestCase, then it executes its block to gather
> >> examples, by using a modified it() method as follows:
> >> - it "should baa" dynamically creates a method in SheepTest called
> >> test_should_baa that looks like this:
> >> cls.define_method :test_should_baa do
> >>     begin
> >>        alert_listeners(:starting)
> >>        run_describe_block_with_it_method_disabled # so helper methods
> >> are defined
> >>        run_the_actual_example_block
> >>        alert_listeners(:succeeded)
> >>     rescue
> >>        alert_listeners(:failed)
> >>        raise
> >>     end
> >> end
> >>
> >> - Any before(:each) or after(:each) blocks get added to lists inside
> >> SheepTest to be invoked by  boilerplate SheepTest#set_up/tear_down
> >> methods.
> >> - before :all and after :all would be more tricky, but they are
> >> discouraged anyway.
> >>
> >
> > It's more like the ! ruby methods. It's dangerous, there is a non
> > dangerous alternative and you should know precisely what you're doing.
> > (perhaps we should rename it before! to follow that convention).
>
> I always thought that that was a LISP/Scheme convention - the
> question mark signifying a boolean return value, and the exclamation
> point signifying an "unsafe" function - unsafe in the Haskell/
> functional way of thinking (i.e. change the state of an object).
> Obviously Ruby isn't a functional language, so I've always been a
> little bit curious as to what is considered "dangerous".

I don't think of ! as dangerous. To me it means "do this to yourself."
When you say list.reject { ... } you get a new list back with the
appropriate items removed. When you say list.reject! { ... }, those
items are actually removed from the list you're sending the message
to. Make sense?


>
> Scott
>
>
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