[rspec-users] Specifying mixins
tom at experthuman.com
Thu Nov 1 08:33:11 EDT 2007
Can anyone share some accumulated wisdom about the best way to spec
mixins in general, and (Jamis Buck-style) ActiveRecord "concerns" in
The standard situation here is that there's a bunch of functionality,
related by concept if not by implementation, that one wants to inherit
in many different classes (e.g. ActiveRecord models) without having to
actually use subclassing -- straightforward enough. But since BDD best
practice encourages one expectation per example and no mocking in the
behaviour setup, the specification for this shared functionality is
often spread across many behaviours, each of which may need to do its
own setup and teardown.
So, how best to mix the mixin spec in with the spec for each class
that uses the mixin (IYSWIM)? I've tried several permutations of
helpers, spec mixins, shared-shared behaviours and so on, but can't
find anything which is persuasively neat and DRY while still working
reliably. One point of contention is that the mixin's behaviours might
need to do things like instantiate the target class with specific
arguments in before :each (or call some other class method, if the
mixin provides some) so it's not really good enough for the target
spec to just squirrel away a prebuilt object in an instance variable.
Any advice, please?
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