Add test to verify that the new :inverse_of association option will indeed fix the validation problem for a belongs_to relationship that validates_presence_of the parent, when both the parent and the child are new (in-memory) records. Also check that this works when the parents adds child via nested_attributes_for.

Lastly, add a require 'models/pet' to association_validation_test.rb, so that test can be run independently (was failing due to that missing dependency). [#2815 status:resolved]

Signed-off-by: José Valim <jose.valim@gmail.com>

activerecord/test/cases/nested_attributes_test.rb

@@ -4,6 +4,8 @@ require "models/ship"
 require "models/bird"
 require "models/parrot"
 require "models/treasure"
+require "models/man"
+require "models/interest"
 require 'active_support/hash_with_indifferent_access'
 
 module AssertRaiseWithMessage
@@ -470,6 +472,41 @@ module NestedAttributesOnACollectionAssociationTests
     assert Pirate.reflect_on_association(@association_name).options[:autosave]
   end
 
+  def test_validate_presence_of_parent__works_with_inverse_of
+    Man.accepts_nested_attributes_for(:interests)
+    assert_equal :man, Man.reflect_on_association(:interests).options[:inverse_of]
+    assert_equal :interests, Interest.reflect_on_association(:man).options[:inverse_of]
+
+    repair_validations(Interest) do
+      Interest.validates_presence_of(:man)
+      assert_difference 'Man.count' do
+        assert_difference 'Interest.count', 2 do
+          man = Man.create!(:name => 'John',
+                            :interests_attributes => [{:topic=>'Cars'}, {:topic=>'Sports'}])
+          assert_equal 2, man.interests.count
+        end
+      end
+    end
+  end
+
+  def test_validate_presence_of_parent__fails_without_inverse_of
+    Man.accepts_nested_attributes_for(:interests)
+    Man.reflect_on_association(:interests).options.delete(:inverse_of)
+    Interest.reflect_on_association(:man).options.delete(:inverse_of)
+
+    repair_validations(Interest) do
+      Interest.validates_presence_of(:man)
+      assert_no_difference ['Man.count', 'Interest.count'] do
+        man = Man.create(:name => 'John',
+                         :interests_attributes => [{:topic=>'Cars'}, {:topic=>'Sports'}])
+        assert !man.errors[:interests_man].empty?
+      end
+    end
+    # restore :inverse_of
+    Man.reflect_on_association(:interests).options[:inverse_of] = :man
+    Interest.reflect_on_association(:man).options[:inverse_of] = :interests
+  end
+
   private
 
   def association_setter

activerecord/test/cases/validations/association_validation_test.rb

@@ -3,6 +3,9 @@ require "cases/helper"
 require 'models/topic'
 require 'models/reply'
 require 'models/owner'
+require 'models/pet'
+require 'models/man'
+require 'models/interest'
 
 class AssociationValidationTest < ActiveRecord::TestCase
   fixtures :topics, :owners
@@ -98,4 +101,24 @@ class AssociationValidationTest < ActiveRecord::TestCase
       end
     end
   end
+
+  def test_validates_presence_of_belongs_to_association__parent_is_new_record
+    repair_validations(Interest) do
+      # Note that Interest and Man have the :inverse_of option set
+      Interest.validates_presence_of(:man)
+      man = Man.new(:name => 'John')
+      interest = man.interests.build(:topic => 'Airplanes')
+      assert interest.valid?, "Expected interest to be valid, but was not. Interest should have a man object associated"
+    end
+  end
+
+  def test_validates_presence_of_belongs_to_association__existing_parent
+    repair_validations(Interest) do
+      Interest.validates_presence_of(:man)
+      man = Man.create!(:name => 'John')
+      interest = man.interests.build(:topic => 'Airplanes')
+      assert interest.valid?, "Expected interest to be valid, but was not. Interest should have a man object associated"
+    end
+  end
+
 end