1 files changed, 35 insertions, 7 deletions
diff --git a/activerecord/test/cases/associations/required_test.rb b/activerecord/test/cases/associations/required_test.rb
index f8b686721e..45e1803858 100644
--- a/activerecord/test/cases/associations/required_test.rb
+++ b/activerecord/test/cases/associations/required_test.rb
@@ -22,14 +22,21 @@ class RequiredAssociationsTest < ActiveRecord::TestCase
     @connection.drop_table "children", if_exists: true
   end
 
-  test "belongs_to associations are not required by default" do
-    model = subclass_of(Child) do
-      belongs_to :parent, inverse_of: false,
-        class_name: "RequiredAssociationsTest::Parent"
-    end
+  test "belongs_to associations can be optional by default" do
+    begin
+      original_value = ActiveRecord::Base.belongs_to_required_by_default
+      ActiveRecord::Base.belongs_to_required_by_default = false
+
+      model = subclass_of(Child) do
+        belongs_to :parent, inverse_of: false,
+          class_name: "RequiredAssociationsTest::Parent"
+      end
 
-    assert model.new.save
-    assert model.new(parent: Parent.new).save
+      assert model.new.save
+      assert model.new(parent: Parent.new).save
+    ensure
+      ActiveRecord::Base.belongs_to_required_by_default = original_value
+    end
   end
 
   test "required belongs_to associations have presence validated" do
@@ -46,6 +53,27 @@ class RequiredAssociationsTest < ActiveRecord::TestCase
     assert record.save
   end
 
+  test "belongs_to associations can be required by default" do
+    begin
+      original_value = ActiveRecord::Base.belongs_to_required_by_default
+      ActiveRecord::Base.belongs_to_required_by_default = true
+
+      model = subclass_of(Child) do
+        belongs_to :parent, inverse_of: false,
+          class_name: "RequiredAssociationsTest::Parent"
+      end
+
+      record = model.new
+      assert_not record.save
+      assert_equal ["Parent must exist"], record.errors.full_messages
+
+      record.parent = Parent.new
+      assert record.save
+    ensure
+      ActiveRecord::Base.belongs_to_required_by_default = original_value
+    end
+  end
+
   test "has_one associations are not required by default" do
     model = subclass_of(Parent) do
       has_one :child, inverse_of: false,