GIANT ROBOTS SMASHING INTO OTHER GIANT ROBOTS

Written by thoughtbot

Testing Named Scope

We’re huge fans of NamedScope here at Thoughtbot. It does wonders for finder reuse and clarity. Unfortunately, it also creates a large number of finders that all must be tested, where the old method may have only created one.

To help out with the testing of simple named_scope definitions, we added a helper to Shoulda, should_have_named_scope:

class User < ActiveRecord::Base
  named_scope :old,      :conditions => "age > 50"
  named_scope :eighteen, :conditions => { :age => 18 }
  named_scope :recent,   lambda {|count| { :limit => count } }
end

class UserTest < Test::Unit::TestCase
  should_have_named_scope :old,       :conditions => "age > 50"
  should_have_named_scope :eighteen,  :conditions => { :age => 18 }
  should_have_named_scope 'recent(5)', :limit => 5
  should_have_named_scope 'recent(1)', :limit => 1
end

Now for complex methods, where the options returned by the

has_finder are hairier than a simple limit or a single column condition, we would also write black box tests. But this helper is great for those simpler calls.