Association matchers support :autosave option

has_one, has_many, belongs_to, and has_and_belongs_to_many relationships can
have an `:autosave` option, which causes the relevant associated records to be
automatically saved when their parent is saved.

This is based on a PR by @calebthompson, which I've brought up to date
with master.

NEWS.md

@@ -3,6 +3,8 @@
 * Association matchers now test that the model being referred to (either
   implicitly or explicitly, using `:class_name`) actually exists.
 
+* Add ability to test `:autosave` option on associations.
+
 # v 2.5.0
 
 * Fix Rails/Test::Unit integration to ensure that the test case classes we are

lib/shoulda/matchers/active_record/association_matcher.rb

@@ -28,6 +28,8 @@ module Shoulda # :nodoc:
       # * <tt>dependent</tt> - tests that the association makes use of the
       #   dependent option.
       # * <tt>:class_name</tt> - tests that the association resoves to class_name.
+      # * <tt>:autosave</tt> - tests that the association makes use of the
+      #   autosave option.
       # * <tt>:validate</tt> - tests that the association makes use of the validate
       # option.
       #
@@ -48,6 +50,8 @@ module Shoulda # :nodoc:
       # * <tt>:dependent</tt> - tests that the association makes use of the
       #   dependent option.
       # * <tt>:class_name</tt> - tests that the association resolves to class_name.
+      # * <tt>:autosave</tt> - tests that the association makes use of the
+      #   autosave option.
       # * <tt>:validate</tt> - tests that the association makes use of the validate
       # option.
       #
@@ -120,6 +124,11 @@ module Shoulda # :nodoc:
           self
         end
 
+        def autosave(autosave)
+          @options[:autosave] = autosave
+          self
+        end
+
         def class_name(class_name)
           @options[:class_name] = class_name
           self
@@ -163,6 +172,7 @@ module Shoulda # :nodoc:
             class_exists? &&
             foreign_key_exists? &&
             class_name_correct? &&
+            autosave_correct? &&
             conditions_correct? &&
             join_table_exists? &&
             validate_correct? &&
@@ -266,6 +276,19 @@ module Shoulda # :nodoc:
           false
         end
 
+        def autosave_correct?
+          if options.key?(:autosave)
+            if option_verifier.correct_for_boolean?(:autosave, options[:autosave])
+              true
+            else
+              @missing = "#{name} should have autosave set to #{options[:autosave]}"
+              false
+            end
+          else
+            true
+          end
+        end
+
         def conditions_correct?
           if options.key?(:conditions)
             if option_verifier.correct_for_relation_clause?(:conditions, options[:conditions])

spec/shoulda/matchers/active_record/association_matcher_spec.rb

@@ -116,6 +116,26 @@ describe Shoulda::Matchers::ActiveRecord::AssociationMatcher do
       }.to fail_with_message(message)
     end
 
+    it 'accepts an association with a matching :autosave option' do
+      define_model :parent, :adopter => :boolean
+      define_model :child, :parent_id => :integer do
+        belongs_to :parent, :autosave => true
+      end
+      expect(Child.new).to belong_to(:parent).autosave(true)
+    end
+
+    it 'rejects an association with a non-matching :autosave option with the correct message' do
+      define_model :parent, :adopter => :boolean
+      define_model :child, :parent_id => :integer do
+        belongs_to :parent, :autosave => false
+      end
+
+      message = 'Expected Child to have a belongs_to association called parent (parent should have autosave set to true)'
+      expect {
+        expect(Child.new).to belong_to(:parent).autosave(true)
+      }.to fail_with_message(message)
+    end
+
     context 'an association with a :validate option' do
       [false, true].each do |validate_value|
         context "when the model has validate: #{validate_value}" do
@@ -380,6 +400,26 @@ describe Shoulda::Matchers::ActiveRecord::AssociationMatcher do
       }.to fail_with_message(message)
     end
 
+    it 'accepts an association with a matching :autosave option' do
+      define_model :child, :parent_id => :integer
+      define_model :parent do
+        has_many :children, :autosave => true
+      end
+      expect(Parent.new).to have_many(:children).autosave(true)
+    end
+
+    it 'rejects an association with a non-matching :autosave option with the correct message' do
+      define_model :child, :parent_id => :integer
+      define_model :parent do
+        has_many :children, :autosave => false
+      end
+
+      message = 'Expected Parent to have a has_many association called children (children should have autosave set to true)'
+      expect {
+        expect(Parent.new).to have_many(:children).autosave(true)
+      }.to fail_with_message(message)
+    end
+
     context 'validate' do
       it 'accepts when the :validate option matches' do
         expect(having_many_children(validate: false)).to have_many(:children).validate(false)
@@ -530,6 +570,26 @@ describe Shoulda::Matchers::ActiveRecord::AssociationMatcher do
       expect(having_one_detail).to have_one(:detail).class_name('Detail')
     end
 
+    it 'accepts an association with a matching :autosave option' do
+      define_model :detail, :person_id => :integer, :disabled => :boolean
+      define_model :person do
+        has_one :detail, :autosave => true
+      end
+      expect(Person.new).to have_one(:detail).autosave(true)
+    end
+
+    it 'rejects an association with a non-matching :autosave option with the correct message' do
+      define_model :detail, :person_id => :integer, :disabled => :boolean
+      define_model :person do
+        has_one :detail, :autosave => false
+      end
+
+      message = 'Expected Person to have a has_one association called detail (detail should have autosave set to true)'
+      expect {
+        expect(Person.new).to have_one(:detail).autosave(true)
+      }.to fail_with_message(message)
+    end
+
     it 'accepts an association with a valid :class_name option' do
       define_model :person_detail, person_id: :integer
       define_model :person do
@@ -712,6 +772,30 @@ describe Shoulda::Matchers::ActiveRecord::AssociationMatcher do
       }.to fail_with_message(message)
     end
 
+    it 'accepts an association with a matching :autosave option' do
+      define_model :relatives, :adopted => :boolean
+      define_model :person do
+        has_and_belongs_to_many :relatives, :autosave => true
+      end
+      define_model :people_relative, :person_id   => :integer,
+                                     :relative_id => :integer
+      expect(Person.new).to have_and_belong_to_many(:relatives).autosave(true)
+    end
+
+    it 'rejects an association with a non-matching :autosave option with the correct message' do
+      define_model :relatives, :adopted => :boolean
+      define_model :person do
+        has_and_belongs_to_many :relatives
+      end
+      define_model :people_relative, :person_id   => :integer,
+                                     :relative_id => :integer
+
+      message = 'Expected Person to have a has_and_belongs_to_many association called relatives (relatives should have autosave set to true)'
+      expect {
+        expect(Person.new).to have_and_belong_to_many(:relatives).autosave(true)
+      }.to fail_with_message(message)
+    end
+
     context 'validate' do
       it 'accepts when the :validate option matches' do
         expect(having_and_belonging_to_many_relatives(validate: false)).