El 8/9/2007, a las 2:15, Pat Maddox escribió: > * Descriptions should be broken up based on the required fixture. I > don't split them up until I actually have to. For example, if I'm > writing a Stack class. I'd probably start off with > > [snip] > > For a simple spec like this it's okay. We could factor out the > Stack.new call, and there's one other smell, but we'll get to that in > a minute. > > Now what if we want to peek the stack? > > [snip] > > Now we've got clear duplication in three places: > (1) The constructor > (2) Call to add_item > (3) the 'it' specifier! > > It's clear that the fixture for "should not be empty" and "should let > you peek" are the same. They're also different from the "should be > empty" so we split them up: > > [snip] > > There are two key benefits to that. The first is that it's obvious > where new specifications need to go. The behavior for #pop whether a > stack is empty or has an item is going to be different. Also if you > need some behavior that changes with 3 items, you can probably figure > out that you should create a new description. > > An even bigger benefit is that it minimizes the brain processing > required to figure out a spec. If you create the fixture in the setup > and don't vary it, it's trivial to scan through some simple > expectations. > > This has to do with the smell that I alluded to earlier, which was the > call to add_item. Ideally your example will contain just one > expectation and no other setup. This reduces the concepts that change > from example to example. Change is where bugs pop up most of the > time. So if you're doing setup in an example, then you probably want > to split it out from the current description. In fact, in real life I > would have split the descriptions up immediately after writing the > "should not be empty" example.
Brilliantly written example, very clear! +1 Cheers, Wincent _______________________________________________ rspec-users mailing list [email protected] http://rubyforge.org/mailman/listinfo/rspec-users
