On Fri, Sep 26, 2008 at 12:18 PM, Mark Wilden <[EMAIL PROTECTED]> wrote: > On Fri, Sep 26, 2008 at 9:47 AM, Ashley Moran > <[EMAIL PROTECTED]> wrote: > >> >> (be sure to spec what attributes your classes have if you're scared of >> pollution!) > > As part of the TDD process, I spec all attributes, but this doesn't seem > universal. Is this a misconception? Do people actually make sure that all > columns exist and can be written to and read from?
To me, spec'ing attributes is a red flag. It is not always a bad thing or wrong, but it suggests that the focus is on structure instead of behaviour and results in a lot of unnecessary overhead in your code examples, making them more brittle and more difficult to maintain. For example, let's say we've got a Person model who can be old enough to vote or not. I might start w/ a code example like this: person = Person.new(:birthdate => 17.years.ago) person.should_not be_voting_age Then I'd do the following: * run the example and discover that Person doesn't have a birthdate= method * add and run a migration that adds birthdate * run the example and discover that Person doesn't have a voting_age? method * def voting_age?; false; end * run the example and it passes * add another example for the positive case * etc, etc In that process, adding and running the migration was the implementation step. No need to spec the existence of the field directly, because this example will fail without it. And the failure message will be that the the Person doesn't respond to birthdate=, so it's exactly the feedback I'd want because it would point me right to the problem. That all make sense? Now sometimes there will be some up-front modeling discussions and you may have a sense that a model needs a specific set of fields just because that's what the customer says. In those cases, I'd recommend trying to find something about the object's behaviour to rationalize the presence of those fields. Developer: why do we care about having a birthdate field? Customer: because I want to know how old people are. Developer: why? How will you find out? Customer: we'll want to run demographics reports Developer: why? Customer: they'll help us sell advertising OK, so now we have a feature, Demographics Reports, that warrants the presence of a birthdate field, and it is in THAT context that the birthdate field should come into existence. Hope this all helps. Cheers, David > ///ark > > _______________________________________________ > rspec-users mailing list > rspec-users@rubyforge.org > http://rubyforge.org/mailman/listinfo/rspec-users > _______________________________________________ rspec-users mailing list rspec-users@rubyforge.org http://rubyforge.org/mailman/listinfo/rspec-users
