Association matchers now support :source option

NEWS.md

@@ -13,11 +13,14 @@
 * The `ensure_inclusion_of` matcher now works with a decimal column.
 
 * Fix association matchers on Rails 3 so they work when used in conjunction with
-  a submatcher such as #order and an association that has :include on it.
+  a submatcher such as #order and an association that has `:include` on it.
 
 * Fix a bug where `validate_uniqueness_of` would fail if the attribute under
   test had a limit of fewer than 16 characters.
 
+* You can now test that your `has_many :through` or `has_one :through`
+  associations are defined with a `:source` option.
+
 # v 2.4.0
 
 * Fix a bug with the `validate_numericality_of` matcher that would not allow the

README.md

@@ -618,6 +618,7 @@ The `have_many` matcher tests your `has_many` and `has_many :through` associatio
 class Person < ActiveRecord::Base
   has_many :friends
   has_many :acquaintances, through: :friends
+  has_many :job_offers, through: :friends, source: :opportunities
   has_many :coins, -> { where(condition: 'mint') }
   has_many :shirts, -> { order('color') }
   has_many :hopes, class_name: 'Dream'
@@ -632,6 +633,7 @@ end
 describe Person do
   it { should have_many(:friends) }
   it { should have_many(:acquaintances).through(:friends) }
+  it { should have_many(:job_offers).through(:friends).source(:opportunities) }
   it { should have_many(:coins).conditions(condition: 'mint') }
   it { should have_many(:shirts).order('color') }
   it { should have_many(:hopes).class_name('Dream') }
@@ -646,6 +648,7 @@ end
 class PersonTest < ActiveSupport::TestCase
   should have_many(:friends)
   should have_many(:acquaintances).through(:friends)
+  should have_many(:job_offers).through(:friends).source(:opportunities)
   should have_many(:coins).conditions(condition: 'mint')
   should have_many(:shirts).order('color')
   should have_many(:hopes).class_name('Dream')
@@ -665,6 +668,7 @@ The `have_one` matcher tests your `has_one` and `has_one :through` associations.
 class Person < ActiveRecord::Base
   has_one :partner
   has_one :life, through: :partner
+  has_one :car, through: :partner, source: :vehicle
   has_one :pet, -> { where('weight < 80') }
   has_one :focus, -> { order('priority desc') }
   has_one :chance, class_name: 'Opportunity'
@@ -677,6 +681,7 @@ end
 describe Person do
   it { should have_one(:partner) }
   it { should have_one(:life).through(:partner) }
+  it { should have_one(:car).through(:partner).source(:vehicle) }
   it { should have_one(:pet).conditions('weight < 80') }
   it { should have_one(:focus).order('priority desc') }
   it { should have_one(:chance).class_name('Opportunity') }

lib/shoulda/matchers/active_record.rb

@@ -3,6 +3,7 @@
 require 'shoulda/matchers/active_record/association_matchers/order_matcher'
 require 'shoulda/matchers/active_record/association_matchers/through_matcher'
 require 'shoulda/matchers/active_record/association_matchers/dependent_matcher'
+require 'shoulda/matchers/active_record/association_matchers/source_matcher'
 require 'shoulda/matchers/active_record/association_matchers/model_reflector'
 require 'shoulda/matchers/active_record/association_matchers/model_reflection'
 require 'shoulda/matchers/active_record/association_matchers/option_verifier'

lib/shoulda/matchers/active_record/association_matcher.rb

@@ -109,6 +109,12 @@ def counter_cache(counter_cache = true)
           self
         end
 
+        def source(source)
+          source_matcher = AssociationMatchers::SourceMatcher.new(source, name)
+          add_submatcher(source_matcher)
+          self
+        end
+
         def conditions(conditions)
           @options[:conditions] = conditions
           self

lib/shoulda/matchers/active_record/association_matchers/source_matcher.rb

@@ -0,0 +1,40 @@
+module Shoulda # :nodoc:
+  module Matchers
+    module ActiveRecord # :nodoc:
+      module AssociationMatchers
+        class SourceMatcher
+          attr_accessor :missing_option
+
+          def initialize(source, name)
+            @source = source
+            @name = name
+            @missing_option = ''
+          end
+
+          def description
+            "source => #{source}"
+          end
+
+          def matches?(subject)
+            self.subject = ModelReflector.new(subject, name)
+
+            if option_verifier.correct_for_string?(:source, source)
+              true
+            else
+              self.missing_option = "#{name} should have #{source} as source option"
+              false
+            end
+          end
+
+          private
+
+          attr_accessor :subject, :source, :name
+
+          def option_verifier
+            @option_verifier ||= OptionVerifier.new(subject)
+          end
+        end
+      end
+    end
+  end
+end

spec/shoulda/matchers/active_record/association_matcher_spec.rb

@@ -282,6 +282,19 @@ def belonging_to_parent(options = {})
       matcher.failure_message_for_should.should =~ /children should have destroy dependency/
     end
 
+    it 'accepts an association with a valid :source option' do
+      having_many_children(:source => :user).
+        should have_many(:children).source(:user)
+    end
+
+    it 'rejects an association with a bad :source option' do
+      matcher = have_many(:children).source(:user)
+
+      having_many_children.should_not matcher
+
+      matcher.failure_message_for_should.should =~ /children should have user as source option/
+    end
+
     it 'accepts an association with a valid :order option' do
       having_many_children(:order => :id).
         should have_many(:children).order(:id)